diff --git a/dist/index.d.ts b/dist/index.d.ts
deleted file mode 100644
index fedf6b3..0000000
--- a/dist/index.d.ts
+++ /dev/null
@@ -1,273 +0,0 @@
-declare module "TWEEN" {
-
-    type EasingFunction = (amount: number) => number;
-
-    /**
-     * The Ease class provides a collection of easing functions for use with tween.js.
-     */
-    const Easing: {
-        Linear: {
-            None: (amount: number) => number;
-        };
-        Quadratic: {
-            In: (amount: number) => number;
-            Out: (amount: number) => number;
-            InOut: (amount: number) => number;
-        };
-        Cubic: {
-            In: (amount: number) => number;
-            Out: (amount: number) => number;
-            InOut: (amount: number) => number;
-        };
-        Quartic: {
-            In: (amount: number) => number;
-            Out: (amount: number) => number;
-            InOut: (amount: number) => number;
-        };
-        Quintic: {
-            In: (amount: number) => number;
-            Out: (amount: number) => number;
-            InOut: (amount: number) => number;
-        };
-        Sinusoidal: {
-            In: (amount: number) => number;
-            Out: (amount: number) => number;
-            InOut: (amount: number) => number;
-        };
-        Exponential: {
-            In: (amount: number) => number;
-            Out: (amount: number) => number;
-            InOut: (amount: number) => number;
-        };
-        Circular: {
-            In: (amount: number) => number;
-            Out: (amount: number) => number;
-            InOut: (amount: number) => number;
-        };
-        Elastic: {
-            In: (amount: number) => number;
-            Out: (amount: number) => number;
-            InOut: (amount: number) => number;
-        };
-        Back: {
-            In: (amount: number) => number;
-            Out: (amount: number) => number;
-            InOut: (amount: number) => number;
-        };
-        Bounce: {
-            In: (amount: number) => number;
-            Out: (amount: number) => number;
-            InOut: (amount: number) => number;
-        };
-    };
-
-    let NOW: () => number;
-
-    /**
-     *
-     */
-    type InterpolationFunction = (v: number[], k: number) => number;
-
-    /**
-     *
-     */
-    const Interpolation: {
-        Linear: (v: number[], k: number) => number;
-        Bezier: (v: number[], k: number) => number;
-        CatmullRom: (v: number[], k: number) => number;
-        Utils: {
-            Linear: (p0: number, p1: number, t: number) => number;
-            Bernstein: (n: number, i: number) => number;
-            Factorial: (n: number) => number;
-            CatmullRom: (p0: number, p1: number, p2: number, p3: number, t: number) => number;
-        };
-    };
-
-    /**
-     * Utils
-     */
-    class Sequence {
-        private static _nextId;
-        static nextId(): number;
-    }
-
-    const VERSION = "18.5.0";
-
-    /**
-     * Controlling groups of tweens
-     *
-     * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
-     * In these cases, you may want to create your own smaller groups of tween
-     */
-    class Main extends Group {
-        version: string;
-        now: () => number;
-        Group: typeof Group;
-        Easing: {
-            Linear: {
-                None: (amount: number) => number;
-            };
-            Quadratic: {
-                In: (amount: number) => number;
-                Out: (amount: number) => number;
-                InOut: (amount: number) => number;
-            };
-            Cubic: {
-                In: (amount: number) => number;
-                Out: (amount: number) => number;
-                InOut: (amount: number) => number;
-            };
-            Quartic: {
-                In: (amount: number) => number;
-                Out: (amount: number) => number;
-                InOut: (amount: number) => number;
-            };
-            Quintic: {
-                In: (amount: number) => number;
-                Out: (amount: number) => number;
-                InOut: (amount: number) => number;
-            };
-            Sinusoidal: {
-                In: (amount: number) => number;
-                Out: (amount: number) => number;
-                InOut: (amount: number) => number;
-            };
-            Exponential: {
-                In: (amount: number) => number;
-                Out: (amount: number) => number;
-                InOut: (amount: number) => number;
-            };
-            Circular: {
-                In: (amount: number) => number;
-                Out: (amount: number) => number;
-                InOut: (amount: number) => number;
-            };
-            Elastic: {
-                In: (amount: number) => number;
-                Out: (amount: number) => number;
-                InOut: (amount: number) => number;
-            };
-            Back: {
-                In: (amount: number) => number;
-                Out: (amount: number) => number;
-                InOut: (amount: number) => number;
-            };
-            Bounce: {
-                In: (amount: number) => number;
-                Out: (amount: number) => number;
-                InOut: (amount: number) => number;
-            };
-        };
-        Interpolation: {
-            Linear: (v: number[], k: number) => number;
-            Bezier: (v: number[], k: number) => number;
-            CatmullRom: (v: number[], k: number) => number;
-            Utils: {
-                Linear: (p0: number, p1: number, t: number) => number;
-                Bernstein: (n: number, i: number) => number;
-                Factorial: (n: number) => number;
-                CatmullRom: (p0: number, p1: number, p2: number, p3: number, t: number) => number;
-            };
-        };
-        nextId: typeof Sequence.nextId;
-        Tween: typeof Tween;
-    }
-
-    const TWEEN: Main;
-
-    /**
-     * Tween.js - Licensed under the MIT license
-     * https://github.com/tweenjs/tween.js
-     * ----------------------------------------------
-     *
-     * See https://github.com/tweenjs/tween.js/graphs/contributors for the full list of contributors.
-     * Thank you all, you're awesome!
-     */
-    
-    
-    
-    class Tween<T extends UnknownProps> {
-        private _object;
-        private _group;
-        private _isPaused;
-        private _pauseStart;
-        private _valuesStart;
-        private _valuesEnd;
-        private _valuesStartRepeat;
-        private _duration;
-        private _initialRepeat;
-        private _repeat;
-        private _repeatDelayTime?;
-        private _yoyo;
-        private _isPlaying;
-        private _reversed;
-        private _delayTime;
-        private _startTime;
-        private _easingFunction;
-        private _interpolationFunction;
-        private _chainedTweens;
-        private _onStartCallback?;
-        private _onStartCallbackFired;
-        private _onUpdateCallback?;
-        private _onRepeatCallback?;
-        private _onCompleteCallback?;
-        private _onStopCallback?;
-        private _id;
-        private _isChainStopped;
-        constructor(_object: T, _group?: Group);
-        getId(): number;
-        isPlaying(): boolean;
-        isPaused(): boolean;
-        to(properties: UnknownProps, duration?: number): this;
-        duration(d: number): this;
-        start(time: number): this;
-        private _setupProperties;
-        stop(): this;
-        end(): this;
-        pause(time: number): this;
-        resume(time: number): this;
-        stopChainedTweens(): this;
-        group(group: Group): this;
-        delay(amount: number): this;
-        repeat(times: number): this;
-        repeatDelay(amount: number): this;
-        yoyo(yoyo: boolean): this;
-        easing(easingFunction: EasingFunction): this;
-        interpolation(interpolationFunction: InterpolationFunction): this;
-        chain(...tweens: Array<Tween<UnknownProps>>): this;
-        onStart(callback: (object: T) => void): this;
-        onUpdate(callback: (object: T, elapsed: number) => void): this;
-        onRepeat(callback: (object: T) => void): this;
-        onComplete(callback: (object: T) => void): this;
-        onStop(callback: (object: T) => void): this;
-        update(time: number): boolean;
-        private _updateProperties;
-        private _handleRelativeValue;
-        private _swapEndStartRepeatValues;
-    }
-
-    type UnknownProps = Record<string, unknown>;
-
-    /**
-     * Controlling groups of tweens
-     *
-     * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
-     * In these cases, you may want to create your own smaller groups of tween
-     */
-    class Group {
-        private _tweens;
-        private _tweensAddedDuringUpdate;
-        getAll(): Array<Tween<UnknownProps>>;
-        removeAll(): void;
-        add(tween: Tween<UnknownProps>): void;
-        remove(tween: Tween<UnknownProps>): void;
-        update(time: number, preserve?: boolean): boolean;
-    }
-
-    export default TWEEN;
-}
-
-declare module "@tweenjs/tween.js" {
-    import TWEEN from "TWEEN";
-    export = TWEEN;
-}
diff --git a/dist/tween.amd.js b/dist/tween.amd.js
index 35b6da3..a81a0d0 100644
--- a/dist/tween.amd.js
+++ b/dist/tween.amd.js
@@ -1,90 +1,4 @@
-define(function () { 'use strict';
-
-    var NOW;
-    // Include a performance.now polyfill.
-    // In node.js, use process.hrtime.
-    // eslint-disable-next-line
-    // @ts-ignore
-    if (typeof self === 'undefined' && typeof process !== 'undefined' && process.hrtime) {
-        NOW = function () {
-            // eslint-disable-next-line
-            // @ts-ignore
-            var time = process.hrtime();
-            // Convert [seconds, nanoseconds] to milliseconds.
-            return time[0] * 1000 + time[1] / 1000000;
-        };
-    }
-    // In a browser, use self.performance.now if it is available.
-    else if (typeof self !== 'undefined' && self.performance !== undefined && self.performance.now !== undefined) {
-        // This must be bound, because directly assigning this function
-        // leads to an invocation exception in Chrome.
-        NOW = self.performance.now.bind(self.performance);
-    }
-    // Use Date.now if it is available.
-    else if (Date.now !== undefined) {
-        NOW = Date.now;
-    }
-    // Otherwise, use 'new Date().getTime()'.
-    else {
-        NOW = function () {
-            return new Date().getTime();
-        };
-    }
-    var NOW$1 = NOW;
-
-    /**
-     * Controlling groups of tweens
-     *
-     * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
-     * In these cases, you may want to create your own smaller groups of tween
-     */
-    var Group = /** @class */ (function () {
-        function Group() {
-            this._tweens = {};
-            this._tweensAddedDuringUpdate = {};
-        }
-        Group.prototype.getAll = function () {
-            var _this = this;
-            return Object.keys(this._tweens).map(function (tweenId) {
-                return _this._tweens[tweenId];
-            });
-        };
-        Group.prototype.removeAll = function () {
-            this._tweens = {};
-        };
-        Group.prototype.add = function (tween) {
-            this._tweens[tween.getId()] = tween;
-            this._tweensAddedDuringUpdate[tween.getId()] = tween;
-        };
-        Group.prototype.remove = function (tween) {
-            delete this._tweens[tween.getId()];
-            delete this._tweensAddedDuringUpdate[tween.getId()];
-        };
-        Group.prototype.update = function (time, preserve) {
-            var tweenIds = Object.keys(this._tweens);
-            if (tweenIds.length === 0) {
-                return false;
-            }
-            time = time !== undefined ? time : NOW$1();
-            // Tweens are updated in "batches". If you add a new tween during an
-            // update, then the new tween will be updated in the next batch.
-            // If you remove a tween during an update, it may or may not be updated.
-            // However, if the removed tween was added during the current batch,
-            // then it will not be updated.
-            while (tweenIds.length > 0) {
-                this._tweensAddedDuringUpdate = {};
-                for (var i = 0; i < tweenIds.length; i++) {
-                    var tween = this._tweens[tweenIds[i]];
-                    if (tween && tween.update(time) === false && !preserve) {
-                        delete this._tweens[tweenIds[i]];
-                    }
-                }
-                tweenIds = Object.keys(this._tweensAddedDuringUpdate);
-            }
-            return true;
-        };
-        return Group;
-    }());
+define(['exports'], function (exports) { 'use strict';
 
     /**
      * The Ease class provides a collection of easing functions for use with tween.js.
@@ -273,6 +187,92 @@ define(function () { 'use strict';
         },
     };
 
+    var now;
+    // Include a performance.now polyfill.
+    // In node.js, use process.hrtime.
+    // eslint-disable-next-line
+    // @ts-ignore
+    if (typeof self === 'undefined' && typeof process !== 'undefined' && process.hrtime) {
+        now = function () {
+            // eslint-disable-next-line
+            // @ts-ignore
+            var time = process.hrtime();
+            // Convert [seconds, nanoseconds] to milliseconds.
+            return time[0] * 1000 + time[1] / 1000000;
+        };
+    }
+    // In a browser, use self.performance.now if it is available.
+    else if (typeof self !== 'undefined' && self.performance !== undefined && self.performance.now !== undefined) {
+        // This must be bound, because directly assigning this function
+        // leads to an invocation exception in Chrome.
+        now = self.performance.now.bind(self.performance);
+    }
+    // Use Date.now if it is available.
+    else if (Date.now !== undefined) {
+        now = Date.now;
+    }
+    // Otherwise, use 'new Date().getTime()'.
+    else {
+        now = function () {
+            return new Date().getTime();
+        };
+    }
+    var now$1 = now;
+
+    /**
+     * Controlling groups of tweens
+     *
+     * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
+     * In these cases, you may want to create your own smaller groups of tween
+     */
+    var Group = /** @class */ (function () {
+        function Group() {
+            this._tweens = {};
+            this._tweensAddedDuringUpdate = {};
+        }
+        Group.prototype.getAll = function () {
+            var _this = this;
+            return Object.keys(this._tweens).map(function (tweenId) {
+                return _this._tweens[tweenId];
+            });
+        };
+        Group.prototype.removeAll = function () {
+            this._tweens = {};
+        };
+        Group.prototype.add = function (tween) {
+            this._tweens[tween.getId()] = tween;
+            this._tweensAddedDuringUpdate[tween.getId()] = tween;
+        };
+        Group.prototype.remove = function (tween) {
+            delete this._tweens[tween.getId()];
+            delete this._tweensAddedDuringUpdate[tween.getId()];
+        };
+        Group.prototype.update = function (time, preserve) {
+            var tweenIds = Object.keys(this._tweens);
+            if (tweenIds.length === 0) {
+                return false;
+            }
+            time = time !== undefined ? time : now$1();
+            // Tweens are updated in "batches". If you add a new tween during an
+            // update, then the new tween will be updated in the next batch.
+            // If you remove a tween during an update, it may or may not be updated.
+            // However, if the removed tween was added during the current batch,
+            // then it will not be updated.
+            while (tweenIds.length > 0) {
+                this._tweensAddedDuringUpdate = {};
+                for (var i = 0; i < tweenIds.length; i++) {
+                    var tween = this._tweens[tweenIds[i]];
+                    if (tween && tween.update(time) === false && !preserve) {
+                        delete this._tweens[tweenIds[i]];
+                    }
+                }
+                tweenIds = Object.keys(this._tweensAddedDuringUpdate);
+            }
+            return true;
+        };
+        return Group;
+    }());
+
     /**
      *
      */
@@ -366,6 +366,8 @@ define(function () { 'use strict';
         return Sequence;
     }());
 
+    var mainGroup = new Group();
+
     /**
      * Tween.js - Licensed under the MIT license
      * https://github.com/tweenjs/tween.js
@@ -376,7 +378,7 @@ define(function () { 'use strict';
      */
     var Tween = /** @class */ (function () {
         function Tween(_object, _group) {
-            if (_group === void 0) { _group = TWEEN; }
+            if (_group === void 0) { _group = mainGroup; }
             this._object = _object;
             this._group = _group;
             this._isPaused = false;
@@ -392,11 +394,11 @@ define(function () { 'use strict';
             this._reversed = false;
             this._delayTime = 0;
             this._startTime = 0;
-            this._easingFunction = TWEEN.Easing.Linear.None;
-            this._interpolationFunction = TWEEN.Interpolation.Linear;
+            this._easingFunction = Easing.Linear.None;
+            this._interpolationFunction = Interpolation.Linear;
             this._chainedTweens = [];
             this._onStartCallbackFired = false;
-            this._id = TWEEN.nextId();
+            this._id = Sequence.nextId();
             this._isChainStopped = false;
         }
         Tween.prototype.getId = function () {
@@ -409,7 +411,6 @@ define(function () { 'use strict';
             return this._isPaused;
         };
         Tween.prototype.to = function (properties, duration) {
-            // to (properties, duration) {
             for (var prop in properties) {
                 this._valuesEnd[prop] = properties[prop];
             }
@@ -443,8 +444,7 @@ define(function () { 'use strict';
             this._isPaused = false;
             this._onStartCallbackFired = false;
             this._isChainStopped = false;
-            this._startTime =
-                time !== undefined ? (typeof time === 'string' ? TWEEN.now() + parseFloat(time) : time) : TWEEN.now();
+            this._startTime = time !== undefined ? (typeof time === 'string' ? now$1() + parseFloat(time) : time) : now$1();
             this._startTime += this._delayTime;
             this._setupProperties(this._object, this._valuesStart, this._valuesEnd, this._valuesStartRepeat);
             return this;
@@ -533,7 +533,7 @@ define(function () { 'use strict';
                 return this;
             }
             this._isPaused = true;
-            this._pauseStart = time === undefined ? TWEEN.now() : time;
+            this._pauseStart = time === undefined ? now$1() : time;
             // eslint-disable-next-line
             // @ts-ignore FIXME?
             this._group.remove(this);
@@ -544,7 +544,7 @@ define(function () { 'use strict';
                 return this;
             }
             this._isPaused = false;
-            this._startTime += (time === undefined ? TWEEN.now() : time) - this._pauseStart;
+            this._startTime += (time === undefined ? now$1() : time) - this._pauseStart;
             this._pauseStart = 0;
             // eslint-disable-next-line
             // @ts-ignore FIXME?
@@ -617,6 +617,7 @@ define(function () { 'use strict';
         Tween.prototype.update = function (time) {
             var property;
             var elapsed;
+            time = time !== undefined ? time : now$1();
             var endTime = this._startTime + this._duration;
             if (time > endTime && !this._isPlaying) {
                 return false;
@@ -746,7 +747,7 @@ define(function () { 'use strict';
         return Tween;
     }());
 
-    var VERSION = '18.5.0';
+    var VERSION = '18.6.1';
 
     /**
      * Tween.js - Licensed under the MIT license
@@ -756,42 +757,54 @@ define(function () { 'use strict';
      * See https://github.com/tweenjs/tween.js/graphs/contributors for the full list of contributors.
      * Thank you all, you're awesome!
      */
-    var __extends = (this && this.__extends) || (function () {
-        var extendStatics = function (d, b) {
-            extendStatics = Object.setPrototypeOf ||
-                ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
-                function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
-            return extendStatics(d, b);
-        };
-        return function (d, b) {
-            extendStatics(d, b);
-            function __() { this.constructor = d; }
-            d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-        };
-    })();
+    var nextId = Sequence.nextId;
     /**
      * Controlling groups of tweens
      *
      * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
-     * In these cases, you may want to create your own smaller groups of tween
+     * In these cases, you may want to create your own smaller groups of tweens.
      */
-    var Main = /** @class */ (function (_super) {
-        __extends(Main, _super);
-        function Main() {
-            var _this = _super !== null && _super.apply(this, arguments) || this;
-            _this.version = VERSION;
-            _this.now = NOW$1;
-            _this.Group = Group;
-            _this.Easing = Easing;
-            _this.Interpolation = Interpolation;
-            _this.nextId = Sequence.nextId;
-            _this.Tween = Tween;
-            return _this;
-        }
-        return Main;
-    }(Group));
-    var TWEEN = new Main();
+    var TWEEN = mainGroup;
+    // This is the best way to export things in a way that's compatible with both ES
+    // Modules and CommonJS, without build hacks, and so as not to break the
+    // existing API.
+    // https://github.com/rollup/rollup/issues/1961#issuecomment-423037881
+    var getAll = TWEEN.getAll.bind(TWEEN);
+    var removeAll = TWEEN.removeAll.bind(TWEEN);
+    var add = TWEEN.add.bind(TWEEN);
+    var remove = TWEEN.remove.bind(TWEEN);
+    var update = TWEEN.update.bind(TWEEN);
+    var exports$1 = {
+        Easing: Easing,
+        Group: Group,
+        Interpolation: Interpolation,
+        now: now$1,
+        Sequence: Sequence,
+        nextId: nextId,
+        Tween: Tween,
+        VERSION: VERSION,
+        getAll: getAll,
+        removeAll: removeAll,
+        add: add,
+        remove: remove,
+        update: update,
+    };
 
-    return TWEEN;
+    exports.Easing = Easing;
+    exports.Group = Group;
+    exports.Interpolation = Interpolation;
+    exports.Sequence = Sequence;
+    exports.Tween = Tween;
+    exports.VERSION = VERSION;
+    exports.add = add;
+    exports.default = exports$1;
+    exports.getAll = getAll;
+    exports.nextId = nextId;
+    exports.now = now$1;
+    exports.remove = remove;
+    exports.removeAll = removeAll;
+    exports.update = update;
+
+    Object.defineProperty(exports, '__esModule', { value: true });
 
 });
diff --git a/dist/tween.cjs.js b/dist/tween.cjs.js
index 4665e43..0137626 100644
--- a/dist/tween.cjs.js
+++ b/dist/tween.cjs.js
@@ -1,90 +1,6 @@
 'use strict';
 
-var NOW;
-// Include a performance.now polyfill.
-// In node.js, use process.hrtime.
-// eslint-disable-next-line
-// @ts-ignore
-if (typeof self === 'undefined' && typeof process !== 'undefined' && process.hrtime) {
-    NOW = function () {
-        // eslint-disable-next-line
-        // @ts-ignore
-        var time = process.hrtime();
-        // Convert [seconds, nanoseconds] to milliseconds.
-        return time[0] * 1000 + time[1] / 1000000;
-    };
-}
-// In a browser, use self.performance.now if it is available.
-else if (typeof self !== 'undefined' && self.performance !== undefined && self.performance.now !== undefined) {
-    // This must be bound, because directly assigning this function
-    // leads to an invocation exception in Chrome.
-    NOW = self.performance.now.bind(self.performance);
-}
-// Use Date.now if it is available.
-else if (Date.now !== undefined) {
-    NOW = Date.now;
-}
-// Otherwise, use 'new Date().getTime()'.
-else {
-    NOW = function () {
-        return new Date().getTime();
-    };
-}
-var NOW$1 = NOW;
-
-/**
- * Controlling groups of tweens
- *
- * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
- * In these cases, you may want to create your own smaller groups of tween
- */
-var Group = /** @class */ (function () {
-    function Group() {
-        this._tweens = {};
-        this._tweensAddedDuringUpdate = {};
-    }
-    Group.prototype.getAll = function () {
-        var _this = this;
-        return Object.keys(this._tweens).map(function (tweenId) {
-            return _this._tweens[tweenId];
-        });
-    };
-    Group.prototype.removeAll = function () {
-        this._tweens = {};
-    };
-    Group.prototype.add = function (tween) {
-        this._tweens[tween.getId()] = tween;
-        this._tweensAddedDuringUpdate[tween.getId()] = tween;
-    };
-    Group.prototype.remove = function (tween) {
-        delete this._tweens[tween.getId()];
-        delete this._tweensAddedDuringUpdate[tween.getId()];
-    };
-    Group.prototype.update = function (time, preserve) {
-        var tweenIds = Object.keys(this._tweens);
-        if (tweenIds.length === 0) {
-            return false;
-        }
-        time = time !== undefined ? time : NOW$1();
-        // Tweens are updated in "batches". If you add a new tween during an
-        // update, then the new tween will be updated in the next batch.
-        // If you remove a tween during an update, it may or may not be updated.
-        // However, if the removed tween was added during the current batch,
-        // then it will not be updated.
-        while (tweenIds.length > 0) {
-            this._tweensAddedDuringUpdate = {};
-            for (var i = 0; i < tweenIds.length; i++) {
-                var tween = this._tweens[tweenIds[i]];
-                if (tween && tween.update(time) === false && !preserve) {
-                    delete this._tweens[tweenIds[i]];
-                }
-            }
-            tweenIds = Object.keys(this._tweensAddedDuringUpdate);
-        }
-        return true;
-    };
-    return Group;
-}());
+Object.defineProperty(exports, '__esModule', { value: true });
 
 /**
  * The Ease class provides a collection of easing functions for use with tween.js.
@@ -273,6 +189,92 @@ var Easing = {
     },
 };
 
+var now;
+// Include a performance.now polyfill.
+// In node.js, use process.hrtime.
+// eslint-disable-next-line
+// @ts-ignore
+if (typeof self === 'undefined' && typeof process !== 'undefined' && process.hrtime) {
+    now = function () {
+        // eslint-disable-next-line
+        // @ts-ignore
+        var time = process.hrtime();
+        // Convert [seconds, nanoseconds] to milliseconds.
+        return time[0] * 1000 + time[1] / 1000000;
+    };
+}
+// In a browser, use self.performance.now if it is available.
+else if (typeof self !== 'undefined' && self.performance !== undefined && self.performance.now !== undefined) {
+    // This must be bound, because directly assigning this function
+    // leads to an invocation exception in Chrome.
+    now = self.performance.now.bind(self.performance);
+}
+// Use Date.now if it is available.
+else if (Date.now !== undefined) {
+    now = Date.now;
+}
+// Otherwise, use 'new Date().getTime()'.
+else {
+    now = function () {
+        return new Date().getTime();
+    };
+}
+var now$1 = now;
+
+/**
+ * Controlling groups of tweens
+ *
+ * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
+ * In these cases, you may want to create your own smaller groups of tween
+ */
+var Group = /** @class */ (function () {
+    function Group() {
+        this._tweens = {};
+        this._tweensAddedDuringUpdate = {};
+    }
+    Group.prototype.getAll = function () {
+        var _this = this;
+        return Object.keys(this._tweens).map(function (tweenId) {
+            return _this._tweens[tweenId];
+        });
+    };
+    Group.prototype.removeAll = function () {
+        this._tweens = {};
+    };
+    Group.prototype.add = function (tween) {
+        this._tweens[tween.getId()] = tween;
+        this._tweensAddedDuringUpdate[tween.getId()] = tween;
+    };
+    Group.prototype.remove = function (tween) {
+        delete this._tweens[tween.getId()];
+        delete this._tweensAddedDuringUpdate[tween.getId()];
+    };
+    Group.prototype.update = function (time, preserve) {
+        var tweenIds = Object.keys(this._tweens);
+        if (tweenIds.length === 0) {
+            return false;
+        }
+        time = time !== undefined ? time : now$1();
+        // Tweens are updated in "batches". If you add a new tween during an
+        // update, then the new tween will be updated in the next batch.
+        // If you remove a tween during an update, it may or may not be updated.
+        // However, if the removed tween was added during the current batch,
+        // then it will not be updated.
+        while (tweenIds.length > 0) {
+            this._tweensAddedDuringUpdate = {};
+            for (var i = 0; i < tweenIds.length; i++) {
+                var tween = this._tweens[tweenIds[i]];
+                if (tween && tween.update(time) === false && !preserve) {
+                    delete this._tweens[tweenIds[i]];
+                }
+            }
+            tweenIds = Object.keys(this._tweensAddedDuringUpdate);
+        }
+        return true;
+    };
+    return Group;
+}());
+
 /**
  *
  */
@@ -366,6 +368,8 @@ var Sequence = /** @class */ (function () {
     return Sequence;
 }());
 
+var mainGroup = new Group();
+
 /**
  * Tween.js - Licensed under the MIT license
  * https://github.com/tweenjs/tween.js
@@ -376,7 +380,7 @@ var Sequence = /** @class */ (function () {
  */
 var Tween = /** @class */ (function () {
     function Tween(_object, _group) {
-        if (_group === void 0) { _group = TWEEN; }
+        if (_group === void 0) { _group = mainGroup; }
         this._object = _object;
         this._group = _group;
         this._isPaused = false;
@@ -392,11 +396,11 @@ var Tween = /** @class */ (function () {
         this._reversed = false;
         this._delayTime = 0;
         this._startTime = 0;
-        this._easingFunction = TWEEN.Easing.Linear.None;
-        this._interpolationFunction = TWEEN.Interpolation.Linear;
+        this._easingFunction = Easing.Linear.None;
+        this._interpolationFunction = Interpolation.Linear;
         this._chainedTweens = [];
         this._onStartCallbackFired = false;
-        this._id = TWEEN.nextId();
+        this._id = Sequence.nextId();
         this._isChainStopped = false;
     }
     Tween.prototype.getId = function () {
@@ -409,7 +413,6 @@ var Tween = /** @class */ (function () {
         return this._isPaused;
     };
     Tween.prototype.to = function (properties, duration) {
-        // to (properties, duration) {
         for (var prop in properties) {
             this._valuesEnd[prop] = properties[prop];
         }
@@ -443,8 +446,7 @@ var Tween = /** @class */ (function () {
         this._isPaused = false;
         this._onStartCallbackFired = false;
         this._isChainStopped = false;
-        this._startTime =
-            time !== undefined ? (typeof time === 'string' ? TWEEN.now() + parseFloat(time) : time) : TWEEN.now();
+        this._startTime = time !== undefined ? (typeof time === 'string' ? now$1() + parseFloat(time) : time) : now$1();
         this._startTime += this._delayTime;
         this._setupProperties(this._object, this._valuesStart, this._valuesEnd, this._valuesStartRepeat);
         return this;
@@ -533,7 +535,7 @@ var Tween = /** @class */ (function () {
             return this;
         }
         this._isPaused = true;
-        this._pauseStart = time === undefined ? TWEEN.now() : time;
+        this._pauseStart = time === undefined ? now$1() : time;
         // eslint-disable-next-line
         // @ts-ignore FIXME?
         this._group.remove(this);
@@ -544,7 +546,7 @@ var Tween = /** @class */ (function () {
             return this;
         }
         this._isPaused = false;
-        this._startTime += (time === undefined ? TWEEN.now() : time) - this._pauseStart;
+        this._startTime += (time === undefined ? now$1() : time) - this._pauseStart;
         this._pauseStart = 0;
         // eslint-disable-next-line
         // @ts-ignore FIXME?
@@ -617,6 +619,7 @@ var Tween = /** @class */ (function () {
     Tween.prototype.update = function (time) {
         var property;
         var elapsed;
+        time = time !== undefined ? time : now$1();
         var endTime = this._startTime + this._duration;
         if (time > endTime && !this._isPlaying) {
             return false;
@@ -746,7 +749,7 @@ var Tween = /** @class */ (function () {
     return Tween;
 }());
 
-var VERSION = '18.5.0';
+var VERSION = '18.6.1';
 
 /**
  * Tween.js - Licensed under the MIT license
@@ -756,40 +759,50 @@ var VERSION = '18.5.0';
  * See https://github.com/tweenjs/tween.js/graphs/contributors for the full list of contributors.
  * Thank you all, you're awesome!
  */
-var __extends = (this && this.__extends) || (function () {
-    var extendStatics = function (d, b) {
-        extendStatics = Object.setPrototypeOf ||
-            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
-            function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
-        return extendStatics(d, b);
-    };
-    return function (d, b) {
-        extendStatics(d, b);
-        function __() { this.constructor = d; }
-        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-    };
-})();
+var nextId = Sequence.nextId;
 /**
  * Controlling groups of tweens
  *
  * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
- * In these cases, you may want to create your own smaller groups of tween
+ * In these cases, you may want to create your own smaller groups of tweens.
  */
-var Main = /** @class */ (function (_super) {
-    __extends(Main, _super);
-    function Main() {
-        var _this = _super !== null && _super.apply(this, arguments) || this;
-        _this.version = VERSION;
-        _this.now = NOW$1;
-        _this.Group = Group;
-        _this.Easing = Easing;
-        _this.Interpolation = Interpolation;
-        _this.nextId = Sequence.nextId;
-        _this.Tween = Tween;
-        return _this;
-    }
-    return Main;
-}(Group));
-var TWEEN = new Main();
+var TWEEN = mainGroup;
+// This is the best way to export things in a way that's compatible with both ES
+// Modules and CommonJS, without build hacks, and so as not to break the
+// existing API.
+// https://github.com/rollup/rollup/issues/1961#issuecomment-423037881
+var getAll = TWEEN.getAll.bind(TWEEN);
+var removeAll = TWEEN.removeAll.bind(TWEEN);
+var add = TWEEN.add.bind(TWEEN);
+var remove = TWEEN.remove.bind(TWEEN);
+var update = TWEEN.update.bind(TWEEN);
+var exports$1 = {
+    Easing: Easing,
+    Group: Group,
+    Interpolation: Interpolation,
+    now: now$1,
+    Sequence: Sequence,
+    nextId: nextId,
+    Tween: Tween,
+    VERSION: VERSION,
+    getAll: getAll,
+    removeAll: removeAll,
+    add: add,
+    remove: remove,
+    update: update,
+};
 
-module.exports = TWEEN;
+exports.Easing = Easing;
+exports.Group = Group;
+exports.Interpolation = Interpolation;
+exports.Sequence = Sequence;
+exports.Tween = Tween;
+exports.VERSION = VERSION;
+exports.add = add;
+exports.default = exports$1;
+exports.getAll = getAll;
+exports.nextId = nextId;
+exports.now = now$1;
+exports.remove = remove;
+exports.removeAll = removeAll;
+exports.update = update;
diff --git a/dist/tween.d.ts b/dist/tween.d.ts
new file mode 100644
index 0000000..674ace0
--- /dev/null
+++ b/dist/tween.d.ts
@@ -0,0 +1,256 @@
+declare type EasingFunction = (amount: number) => number;
+/**
+ * The Ease class provides a collection of easing functions for use with tween.js.
+ */
+declare const Easing: {
+    Linear: {
+        None: (amount: number) => number;
+    };
+    Quadratic: {
+        In: (amount: number) => number;
+        Out: (amount: number) => number;
+        InOut: (amount: number) => number;
+    };
+    Cubic: {
+        In: (amount: number) => number;
+        Out: (amount: number) => number;
+        InOut: (amount: number) => number;
+    };
+    Quartic: {
+        In: (amount: number) => number;
+        Out: (amount: number) => number;
+        InOut: (amount: number) => number;
+    };
+    Quintic: {
+        In: (amount: number) => number;
+        Out: (amount: number) => number;
+        InOut: (amount: number) => number;
+    };
+    Sinusoidal: {
+        In: (amount: number) => number;
+        Out: (amount: number) => number;
+        InOut: (amount: number) => number;
+    };
+    Exponential: {
+        In: (amount: number) => number;
+        Out: (amount: number) => number;
+        InOut: (amount: number) => number;
+    };
+    Circular: {
+        In: (amount: number) => number;
+        Out: (amount: number) => number;
+        InOut: (amount: number) => number;
+    };
+    Elastic: {
+        In: (amount: number) => number;
+        Out: (amount: number) => number;
+        InOut: (amount: number) => number;
+    };
+    Back: {
+        In: (amount: number) => number;
+        Out: (amount: number) => number;
+        InOut: (amount: number) => number;
+    };
+    Bounce: {
+        In: (amount: number) => number;
+        Out: (amount: number) => number;
+        InOut: (amount: number) => number;
+    };
+};
+
+/**
+ *
+ */
+declare type InterpolationFunction = (v: number[], k: number) => number;
+/**
+ *
+ */
+declare const Interpolation: {
+    Linear: (v: number[], k: number) => number;
+    Bezier: (v: number[], k: number) => number;
+    CatmullRom: (v: number[], k: number) => number;
+    Utils: {
+        Linear: (p0: number, p1: number, t: number) => number;
+        Bernstein: (n: number, i: number) => number;
+        Factorial: (n: number) => number;
+        CatmullRom: (p0: number, p1: number, p2: number, p3: number, t: number) => number;
+    };
+};
+
+declare class Tween<T extends UnknownProps> {
+    private _object;
+    private _group;
+    private _isPaused;
+    private _pauseStart;
+    private _valuesStart;
+    private _valuesEnd;
+    private _valuesStartRepeat;
+    private _duration;
+    private _initialRepeat;
+    private _repeat;
+    private _repeatDelayTime?;
+    private _yoyo;
+    private _isPlaying;
+    private _reversed;
+    private _delayTime;
+    private _startTime;
+    private _easingFunction;
+    private _interpolationFunction;
+    private _chainedTweens;
+    private _onStartCallback?;
+    private _onStartCallbackFired;
+    private _onUpdateCallback?;
+    private _onRepeatCallback?;
+    private _onCompleteCallback?;
+    private _onStopCallback?;
+    private _id;
+    private _isChainStopped;
+    constructor(_object: T, _group?: Group);
+    getId(): number;
+    isPlaying(): boolean;
+    isPaused(): boolean;
+    to(properties: UnknownProps, duration?: number): this;
+    duration(d: number): this;
+    start(time?: number): this;
+    private _setupProperties;
+    stop(): this;
+    end(): this;
+    pause(time: number): this;
+    resume(time: number): this;
+    stopChainedTweens(): this;
+    group(group: Group): this;
+    delay(amount: number): this;
+    repeat(times: number): this;
+    repeatDelay(amount: number): this;
+    yoyo(yoyo: boolean): this;
+    easing(easingFunction: EasingFunction): this;
+    interpolation(interpolationFunction: InterpolationFunction): this;
+    chain(...tweens: Array<Tween<UnknownProps>>): this;
+    onStart(callback: (object: T) => void): this;
+    onUpdate(callback: (object: T, elapsed: number) => void): this;
+    onRepeat(callback: (object: T) => void): this;
+    onComplete(callback: (object: T) => void): this;
+    onStop(callback: (object: T) => void): this;
+    update(time?: number): boolean;
+    private _updateProperties;
+    private _handleRelativeValue;
+    private _swapEndStartRepeatValues;
+}
+declare type UnknownProps = Record<string, unknown>;
+
+/**
+ * Controlling groups of tweens
+ *
+ * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
+ * In these cases, you may want to create your own smaller groups of tween
+ */
+declare class Group {
+    private _tweens;
+    private _tweensAddedDuringUpdate;
+    getAll(): Array<Tween<UnknownProps>>;
+    removeAll(): void;
+    add(tween: Tween<UnknownProps>): void;
+    remove(tween: Tween<UnknownProps>): void;
+    update(time: number, preserve?: boolean): boolean;
+}
+
+declare let now: () => number;
+
+/**
+ * Utils
+ */
+declare class Sequence {
+    private static _nextId;
+    static nextId(): number;
+}
+
+declare const VERSION = "18.6.1";
+
+declare const nextId: typeof Sequence.nextId;
+declare const getAll: () => Tween<Record<string, unknown>>[];
+declare const removeAll: () => void;
+declare const add: (tween: Tween<Record<string, unknown>>) => void;
+declare const remove: (tween: Tween<Record<string, unknown>>) => void;
+declare const update: (time: number, preserve?: boolean | undefined) => boolean;
+declare const exports: {
+    Easing: {
+        Linear: {
+            None: (amount: number) => number;
+        };
+        Quadratic: {
+            In: (amount: number) => number;
+            Out: (amount: number) => number;
+            InOut: (amount: number) => number;
+        };
+        Cubic: {
+            In: (amount: number) => number;
+            Out: (amount: number) => number;
+            InOut: (amount: number) => number;
+        };
+        Quartic: {
+            In: (amount: number) => number;
+            Out: (amount: number) => number;
+            InOut: (amount: number) => number;
+        };
+        Quintic: {
+            In: (amount: number) => number;
+            Out: (amount: number) => number;
+            InOut: (amount: number) => number;
+        };
+        Sinusoidal: {
+            In: (amount: number) => number;
+            Out: (amount: number) => number;
+            InOut: (amount: number) => number;
+        };
+        Exponential: {
+            In: (amount: number) => number;
+            Out: (amount: number) => number;
+            InOut: (amount: number) => number;
+        };
+        Circular: {
+            In: (amount: number) => number;
+            Out: (amount: number) => number;
+            InOut: (amount: number) => number;
+        };
+        Elastic: {
+            In: (amount: number) => number;
+            Out: (amount: number) => number;
+            InOut: (amount: number) => number;
+        };
+        Back: {
+            In: (amount: number) => number;
+            Out: (amount: number) => number;
+            InOut: (amount: number) => number;
+        };
+        Bounce: {
+            In: (amount: number) => number;
+            Out: (amount: number) => number;
+            InOut: (amount: number) => number;
+        };
+    };
+    Group: typeof Group;
+    Interpolation: {
+        Linear: (v: number[], k: number) => number;
+        Bezier: (v: number[], k: number) => number;
+        CatmullRom: (v: number[], k: number) => number;
+        Utils: {
+            Linear: (p0: number, p1: number, t: number) => number;
+            Bernstein: (n: number, i: number) => number;
+            Factorial: (n: number) => number;
+            CatmullRom: (p0: number, p1: number, p2: number, p3: number, t: number) => number;
+        };
+    };
+    now: () => number;
+    Sequence: typeof Sequence;
+    nextId: typeof Sequence.nextId;
+    Tween: typeof Tween;
+    VERSION: string;
+    getAll: () => Tween<Record<string, unknown>>[];
+    removeAll: () => void;
+    add: (tween: Tween<Record<string, unknown>>) => void;
+    remove: (tween: Tween<Record<string, unknown>>) => void;
+    update: (time: number, preserve?: boolean | undefined) => boolean;
+};
+
+export default exports;
+export { Easing, Group, Interpolation, Sequence, Tween, VERSION, add, getAll, nextId, now, remove, removeAll, update };
diff --git a/dist/tween.esm.js b/dist/tween.esm.js
index 22b36ee..276077b 100644
--- a/dist/tween.esm.js
+++ b/dist/tween.esm.js
@@ -1,89 +1,3 @@
-var NOW;
-// Include a performance.now polyfill.
-// In node.js, use process.hrtime.
-// eslint-disable-next-line
-// @ts-ignore
-if (typeof self === 'undefined' && typeof process !== 'undefined' && process.hrtime) {
-    NOW = function () {
-        // eslint-disable-next-line
-        // @ts-ignore
-        var time = process.hrtime();
-        // Convert [seconds, nanoseconds] to milliseconds.
-        return time[0] * 1000 + time[1] / 1000000;
-    };
-}
-// In a browser, use self.performance.now if it is available.
-else if (typeof self !== 'undefined' && self.performance !== undefined && self.performance.now !== undefined) {
-    // This must be bound, because directly assigning this function
-    // leads to an invocation exception in Chrome.
-    NOW = self.performance.now.bind(self.performance);
-}
-// Use Date.now if it is available.
-else if (Date.now !== undefined) {
-    NOW = Date.now;
-}
-// Otherwise, use 'new Date().getTime()'.
-else {
-    NOW = function () {
-        return new Date().getTime();
-    };
-}
-var NOW$1 = NOW;
-
-/**
- * Controlling groups of tweens
- *
- * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
- * In these cases, you may want to create your own smaller groups of tween
- */
-var Group = /** @class */ (function () {
-    function Group() {
-        this._tweens = {};
-        this._tweensAddedDuringUpdate = {};
-    }
-    Group.prototype.getAll = function () {
-        var _this = this;
-        return Object.keys(this._tweens).map(function (tweenId) {
-            return _this._tweens[tweenId];
-        });
-    };
-    Group.prototype.removeAll = function () {
-        this._tweens = {};
-    };
-    Group.prototype.add = function (tween) {
-        this._tweens[tween.getId()] = tween;
-        this._tweensAddedDuringUpdate[tween.getId()] = tween;
-    };
-    Group.prototype.remove = function (tween) {
-        delete this._tweens[tween.getId()];
-        delete this._tweensAddedDuringUpdate[tween.getId()];
-    };
-    Group.prototype.update = function (time, preserve) {
-        var tweenIds = Object.keys(this._tweens);
-        if (tweenIds.length === 0) {
-            return false;
-        }
-        time = time !== undefined ? time : NOW$1();
-        // Tweens are updated in "batches". If you add a new tween during an
-        // update, then the new tween will be updated in the next batch.
-        // If you remove a tween during an update, it may or may not be updated.
-        // However, if the removed tween was added during the current batch,
-        // then it will not be updated.
-        while (tweenIds.length > 0) {
-            this._tweensAddedDuringUpdate = {};
-            for (var i = 0; i < tweenIds.length; i++) {
-                var tween = this._tweens[tweenIds[i]];
-                if (tween && tween.update(time) === false && !preserve) {
-                    delete this._tweens[tweenIds[i]];
-                }
-            }
-            tweenIds = Object.keys(this._tweensAddedDuringUpdate);
-        }
-        return true;
-    };
-    return Group;
-}());
-
 /**
  * The Ease class provides a collection of easing functions for use with tween.js.
  */
@@ -271,6 +185,92 @@ var Easing = {
     },
 };
 
+var now;
+// Include a performance.now polyfill.
+// In node.js, use process.hrtime.
+// eslint-disable-next-line
+// @ts-ignore
+if (typeof self === 'undefined' && typeof process !== 'undefined' && process.hrtime) {
+    now = function () {
+        // eslint-disable-next-line
+        // @ts-ignore
+        var time = process.hrtime();
+        // Convert [seconds, nanoseconds] to milliseconds.
+        return time[0] * 1000 + time[1] / 1000000;
+    };
+}
+// In a browser, use self.performance.now if it is available.
+else if (typeof self !== 'undefined' && self.performance !== undefined && self.performance.now !== undefined) {
+    // This must be bound, because directly assigning this function
+    // leads to an invocation exception in Chrome.
+    now = self.performance.now.bind(self.performance);
+}
+// Use Date.now if it is available.
+else if (Date.now !== undefined) {
+    now = Date.now;
+}
+// Otherwise, use 'new Date().getTime()'.
+else {
+    now = function () {
+        return new Date().getTime();
+    };
+}
+var now$1 = now;
+
+/**
+ * Controlling groups of tweens
+ *
+ * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
+ * In these cases, you may want to create your own smaller groups of tween
+ */
+var Group = /** @class */ (function () {
+    function Group() {
+        this._tweens = {};
+        this._tweensAddedDuringUpdate = {};
+    }
+    Group.prototype.getAll = function () {
+        var _this = this;
+        return Object.keys(this._tweens).map(function (tweenId) {
+            return _this._tweens[tweenId];
+        });
+    };
+    Group.prototype.removeAll = function () {
+        this._tweens = {};
+    };
+    Group.prototype.add = function (tween) {
+        this._tweens[tween.getId()] = tween;
+        this._tweensAddedDuringUpdate[tween.getId()] = tween;
+    };
+    Group.prototype.remove = function (tween) {
+        delete this._tweens[tween.getId()];
+        delete this._tweensAddedDuringUpdate[tween.getId()];
+    };
+    Group.prototype.update = function (time, preserve) {
+        var tweenIds = Object.keys(this._tweens);
+        if (tweenIds.length === 0) {
+            return false;
+        }
+        time = time !== undefined ? time : now$1();
+        // Tweens are updated in "batches". If you add a new tween during an
+        // update, then the new tween will be updated in the next batch.
+        // If you remove a tween during an update, it may or may not be updated.
+        // However, if the removed tween was added during the current batch,
+        // then it will not be updated.
+        while (tweenIds.length > 0) {
+            this._tweensAddedDuringUpdate = {};
+            for (var i = 0; i < tweenIds.length; i++) {
+                var tween = this._tweens[tweenIds[i]];
+                if (tween && tween.update(time) === false && !preserve) {
+                    delete this._tweens[tweenIds[i]];
+                }
+            }
+            tweenIds = Object.keys(this._tweensAddedDuringUpdate);
+        }
+        return true;
+    };
+    return Group;
+}());
+
 /**
  *
  */
@@ -364,6 +364,8 @@ var Sequence = /** @class */ (function () {
     return Sequence;
 }());
 
+var mainGroup = new Group();
+
 /**
  * Tween.js - Licensed under the MIT license
  * https://github.com/tweenjs/tween.js
@@ -374,7 +376,7 @@ var Sequence = /** @class */ (function () {
  */
 var Tween = /** @class */ (function () {
     function Tween(_object, _group) {
-        if (_group === void 0) { _group = TWEEN; }
+        if (_group === void 0) { _group = mainGroup; }
         this._object = _object;
         this._group = _group;
         this._isPaused = false;
@@ -390,11 +392,11 @@ var Tween = /** @class */ (function () {
         this._reversed = false;
         this._delayTime = 0;
         this._startTime = 0;
-        this._easingFunction = TWEEN.Easing.Linear.None;
-        this._interpolationFunction = TWEEN.Interpolation.Linear;
+        this._easingFunction = Easing.Linear.None;
+        this._interpolationFunction = Interpolation.Linear;
         this._chainedTweens = [];
         this._onStartCallbackFired = false;
-        this._id = TWEEN.nextId();
+        this._id = Sequence.nextId();
         this._isChainStopped = false;
     }
     Tween.prototype.getId = function () {
@@ -407,7 +409,6 @@ var Tween = /** @class */ (function () {
         return this._isPaused;
     };
     Tween.prototype.to = function (properties, duration) {
-        // to (properties, duration) {
         for (var prop in properties) {
             this._valuesEnd[prop] = properties[prop];
         }
@@ -441,8 +442,7 @@ var Tween = /** @class */ (function () {
         this._isPaused = false;
         this._onStartCallbackFired = false;
         this._isChainStopped = false;
-        this._startTime =
-            time !== undefined ? (typeof time === 'string' ? TWEEN.now() + parseFloat(time) : time) : TWEEN.now();
+        this._startTime = time !== undefined ? (typeof time === 'string' ? now$1() + parseFloat(time) : time) : now$1();
         this._startTime += this._delayTime;
         this._setupProperties(this._object, this._valuesStart, this._valuesEnd, this._valuesStartRepeat);
         return this;
@@ -531,7 +531,7 @@ var Tween = /** @class */ (function () {
             return this;
         }
         this._isPaused = true;
-        this._pauseStart = time === undefined ? TWEEN.now() : time;
+        this._pauseStart = time === undefined ? now$1() : time;
         // eslint-disable-next-line
         // @ts-ignore FIXME?
         this._group.remove(this);
@@ -542,7 +542,7 @@ var Tween = /** @class */ (function () {
             return this;
         }
         this._isPaused = false;
-        this._startTime += (time === undefined ? TWEEN.now() : time) - this._pauseStart;
+        this._startTime += (time === undefined ? now$1() : time) - this._pauseStart;
         this._pauseStart = 0;
         // eslint-disable-next-line
         // @ts-ignore FIXME?
@@ -615,6 +615,7 @@ var Tween = /** @class */ (function () {
     Tween.prototype.update = function (time) {
         var property;
         var elapsed;
+        time = time !== undefined ? time : now$1();
         var endTime = this._startTime + this._duration;
         if (time > endTime && !this._isPlaying) {
             return false;
@@ -744,7 +745,7 @@ var Tween = /** @class */ (function () {
     return Tween;
 }());
 
-var VERSION = '18.5.0';
+var VERSION = '18.6.1';
 
 /**
  * Tween.js - Licensed under the MIT license
@@ -754,40 +755,38 @@ var VERSION = '18.5.0';
  * See https://github.com/tweenjs/tween.js/graphs/contributors for the full list of contributors.
  * Thank you all, you're awesome!
  */
-var __extends = (this && this.__extends) || (function () {
-    var extendStatics = function (d, b) {
-        extendStatics = Object.setPrototypeOf ||
-            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
-            function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
-        return extendStatics(d, b);
-    };
-    return function (d, b) {
-        extendStatics(d, b);
-        function __() { this.constructor = d; }
-        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-    };
-})();
+var nextId = Sequence.nextId;
 /**
  * Controlling groups of tweens
  *
  * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
- * In these cases, you may want to create your own smaller groups of tween
+ * In these cases, you may want to create your own smaller groups of tweens.
  */
-var Main = /** @class */ (function (_super) {
-    __extends(Main, _super);
-    function Main() {
-        var _this = _super !== null && _super.apply(this, arguments) || this;
-        _this.version = VERSION;
-        _this.now = NOW$1;
-        _this.Group = Group;
-        _this.Easing = Easing;
-        _this.Interpolation = Interpolation;
-        _this.nextId = Sequence.nextId;
-        _this.Tween = Tween;
-        return _this;
-    }
-    return Main;
-}(Group));
-var TWEEN = new Main();
+var TWEEN = mainGroup;
+// This is the best way to export things in a way that's compatible with both ES
+// Modules and CommonJS, without build hacks, and so as not to break the
+// existing API.
+// https://github.com/rollup/rollup/issues/1961#issuecomment-423037881
+var getAll = TWEEN.getAll.bind(TWEEN);
+var removeAll = TWEEN.removeAll.bind(TWEEN);
+var add = TWEEN.add.bind(TWEEN);
+var remove = TWEEN.remove.bind(TWEEN);
+var update = TWEEN.update.bind(TWEEN);
+var exports = {
+    Easing: Easing,
+    Group: Group,
+    Interpolation: Interpolation,
+    now: now$1,
+    Sequence: Sequence,
+    nextId: nextId,
+    Tween: Tween,
+    VERSION: VERSION,
+    getAll: getAll,
+    removeAll: removeAll,
+    add: add,
+    remove: remove,
+    update: update,
+};
 
-export default TWEEN;
+export default exports;
+export { Easing, Group, Interpolation, Sequence, Tween, VERSION, add, getAll, nextId, now$1 as now, remove, removeAll, update };
diff --git a/dist/tween.umd.js b/dist/tween.umd.js
index 7efbae5..cf1b285 100644
--- a/dist/tween.umd.js
+++ b/dist/tween.umd.js
@@ -1,94 +1,8 @@
 (function (global, factory) {
-    typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
-    typeof define === 'function' && define.amd ? define(factory) :
-    (global.TWEEN = factory());
-}(this, (function () { 'use strict';
-
-    var NOW;
-    // Include a performance.now polyfill.
-    // In node.js, use process.hrtime.
-    // eslint-disable-next-line
-    // @ts-ignore
-    if (typeof self === 'undefined' && typeof process !== 'undefined' && process.hrtime) {
-        NOW = function () {
-            // eslint-disable-next-line
-            // @ts-ignore
-            var time = process.hrtime();
-            // Convert [seconds, nanoseconds] to milliseconds.
-            return time[0] * 1000 + time[1] / 1000000;
-        };
-    }
-    // In a browser, use self.performance.now if it is available.
-    else if (typeof self !== 'undefined' && self.performance !== undefined && self.performance.now !== undefined) {
-        // This must be bound, because directly assigning this function
-        // leads to an invocation exception in Chrome.
-        NOW = self.performance.now.bind(self.performance);
-    }
-    // Use Date.now if it is available.
-    else if (Date.now !== undefined) {
-        NOW = Date.now;
-    }
-    // Otherwise, use 'new Date().getTime()'.
-    else {
-        NOW = function () {
-            return new Date().getTime();
-        };
-    }
-    var NOW$1 = NOW;
-
-    /**
-     * Controlling groups of tweens
-     *
-     * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
-     * In these cases, you may want to create your own smaller groups of tween
-     */
-    var Group = /** @class */ (function () {
-        function Group() {
-            this._tweens = {};
-            this._tweensAddedDuringUpdate = {};
-        }
-        Group.prototype.getAll = function () {
-            var _this = this;
-            return Object.keys(this._tweens).map(function (tweenId) {
-                return _this._tweens[tweenId];
-            });
-        };
-        Group.prototype.removeAll = function () {
-            this._tweens = {};
-        };
-        Group.prototype.add = function (tween) {
-            this._tweens[tween.getId()] = tween;
-            this._tweensAddedDuringUpdate[tween.getId()] = tween;
-        };
-        Group.prototype.remove = function (tween) {
-            delete this._tweens[tween.getId()];
-            delete this._tweensAddedDuringUpdate[tween.getId()];
-        };
-        Group.prototype.update = function (time, preserve) {
-            var tweenIds = Object.keys(this._tweens);
-            if (tweenIds.length === 0) {
-                return false;
-            }
-            time = time !== undefined ? time : NOW$1();
-            // Tweens are updated in "batches". If you add a new tween during an
-            // update, then the new tween will be updated in the next batch.
-            // If you remove a tween during an update, it may or may not be updated.
-            // However, if the removed tween was added during the current batch,
-            // then it will not be updated.
-            while (tweenIds.length > 0) {
-                this._tweensAddedDuringUpdate = {};
-                for (var i = 0; i < tweenIds.length; i++) {
-                    var tween = this._tweens[tweenIds[i]];
-                    if (tween && tween.update(time) === false && !preserve) {
-                        delete this._tweens[tweenIds[i]];
-                    }
-                }
-                tweenIds = Object.keys(this._tweensAddedDuringUpdate);
-            }
-            return true;
-        };
-        return Group;
-    }());
+    typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
+    typeof define === 'function' && define.amd ? define(['exports'], factory) :
+    (global = typeof globalThis !== 'undefined' ? globalThis : global || self, factory(global.TWEEN = {}));
+}(this, (function (exports) { 'use strict';
 
     /**
      * The Ease class provides a collection of easing functions for use with tween.js.
@@ -277,6 +191,92 @@
         },
     };
 
+    var now;
+    // Include a performance.now polyfill.
+    // In node.js, use process.hrtime.
+    // eslint-disable-next-line
+    // @ts-ignore
+    if (typeof self === 'undefined' && typeof process !== 'undefined' && process.hrtime) {
+        now = function () {
+            // eslint-disable-next-line
+            // @ts-ignore
+            var time = process.hrtime();
+            // Convert [seconds, nanoseconds] to milliseconds.
+            return time[0] * 1000 + time[1] / 1000000;
+        };
+    }
+    // In a browser, use self.performance.now if it is available.
+    else if (typeof self !== 'undefined' && self.performance !== undefined && self.performance.now !== undefined) {
+        // This must be bound, because directly assigning this function
+        // leads to an invocation exception in Chrome.
+        now = self.performance.now.bind(self.performance);
+    }
+    // Use Date.now if it is available.
+    else if (Date.now !== undefined) {
+        now = Date.now;
+    }
+    // Otherwise, use 'new Date().getTime()'.
+    else {
+        now = function () {
+            return new Date().getTime();
+        };
+    }
+    var now$1 = now;
+
+    /**
+     * Controlling groups of tweens
+     *
+     * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
+     * In these cases, you may want to create your own smaller groups of tween
+     */
+    var Group = /** @class */ (function () {
+        function Group() {
+            this._tweens = {};
+            this._tweensAddedDuringUpdate = {};
+        }
+        Group.prototype.getAll = function () {
+            var _this = this;
+            return Object.keys(this._tweens).map(function (tweenId) {
+                return _this._tweens[tweenId];
+            });
+        };
+        Group.prototype.removeAll = function () {
+            this._tweens = {};
+        };
+        Group.prototype.add = function (tween) {
+            this._tweens[tween.getId()] = tween;
+            this._tweensAddedDuringUpdate[tween.getId()] = tween;
+        };
+        Group.prototype.remove = function (tween) {
+            delete this._tweens[tween.getId()];
+            delete this._tweensAddedDuringUpdate[tween.getId()];
+        };
+        Group.prototype.update = function (time, preserve) {
+            var tweenIds = Object.keys(this._tweens);
+            if (tweenIds.length === 0) {
+                return false;
+            }
+            time = time !== undefined ? time : now$1();
+            // Tweens are updated in "batches". If you add a new tween during an
+            // update, then the new tween will be updated in the next batch.
+            // If you remove a tween during an update, it may or may not be updated.
+            // However, if the removed tween was added during the current batch,
+            // then it will not be updated.
+            while (tweenIds.length > 0) {
+                this._tweensAddedDuringUpdate = {};
+                for (var i = 0; i < tweenIds.length; i++) {
+                    var tween = this._tweens[tweenIds[i]];
+                    if (tween && tween.update(time) === false && !preserve) {
+                        delete this._tweens[tweenIds[i]];
+                    }
+                }
+                tweenIds = Object.keys(this._tweensAddedDuringUpdate);
+            }
+            return true;
+        };
+        return Group;
+    }());
+
     /**
      *
      */
@@ -370,6 +370,8 @@
         return Sequence;
     }());
 
+    var mainGroup = new Group();
+
     /**
      * Tween.js - Licensed under the MIT license
      * https://github.com/tweenjs/tween.js
@@ -380,7 +382,7 @@
      */
     var Tween = /** @class */ (function () {
         function Tween(_object, _group) {
-            if (_group === void 0) { _group = TWEEN; }
+            if (_group === void 0) { _group = mainGroup; }
             this._object = _object;
             this._group = _group;
             this._isPaused = false;
@@ -396,11 +398,11 @@
             this._reversed = false;
             this._delayTime = 0;
             this._startTime = 0;
-            this._easingFunction = TWEEN.Easing.Linear.None;
-            this._interpolationFunction = TWEEN.Interpolation.Linear;
+            this._easingFunction = Easing.Linear.None;
+            this._interpolationFunction = Interpolation.Linear;
             this._chainedTweens = [];
             this._onStartCallbackFired = false;
-            this._id = TWEEN.nextId();
+            this._id = Sequence.nextId();
             this._isChainStopped = false;
         }
         Tween.prototype.getId = function () {
@@ -413,7 +415,6 @@
             return this._isPaused;
         };
         Tween.prototype.to = function (properties, duration) {
-            // to (properties, duration) {
             for (var prop in properties) {
                 this._valuesEnd[prop] = properties[prop];
             }
@@ -447,8 +448,7 @@
             this._isPaused = false;
             this._onStartCallbackFired = false;
             this._isChainStopped = false;
-            this._startTime =
-                time !== undefined ? (typeof time === 'string' ? TWEEN.now() + parseFloat(time) : time) : TWEEN.now();
+            this._startTime = time !== undefined ? (typeof time === 'string' ? now$1() + parseFloat(time) : time) : now$1();
             this._startTime += this._delayTime;
             this._setupProperties(this._object, this._valuesStart, this._valuesEnd, this._valuesStartRepeat);
             return this;
@@ -537,7 +537,7 @@
                 return this;
             }
             this._isPaused = true;
-            this._pauseStart = time === undefined ? TWEEN.now() : time;
+            this._pauseStart = time === undefined ? now$1() : time;
             // eslint-disable-next-line
             // @ts-ignore FIXME?
             this._group.remove(this);
@@ -548,7 +548,7 @@
                 return this;
             }
             this._isPaused = false;
-            this._startTime += (time === undefined ? TWEEN.now() : time) - this._pauseStart;
+            this._startTime += (time === undefined ? now$1() : time) - this._pauseStart;
             this._pauseStart = 0;
             // eslint-disable-next-line
             // @ts-ignore FIXME?
@@ -621,6 +621,7 @@
         Tween.prototype.update = function (time) {
             var property;
             var elapsed;
+            time = time !== undefined ? time : now$1();
             var endTime = this._startTime + this._duration;
             if (time > endTime && !this._isPlaying) {
                 return false;
@@ -750,7 +751,7 @@
         return Tween;
     }());
 
-    var VERSION = '18.5.0';
+    var VERSION = '18.6.1';
 
     /**
      * Tween.js - Licensed under the MIT license
@@ -760,42 +761,54 @@
      * See https://github.com/tweenjs/tween.js/graphs/contributors for the full list of contributors.
      * Thank you all, you're awesome!
      */
-    var __extends = (this && this.__extends) || (function () {
-        var extendStatics = function (d, b) {
-            extendStatics = Object.setPrototypeOf ||
-                ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
-                function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
-            return extendStatics(d, b);
-        };
-        return function (d, b) {
-            extendStatics(d, b);
-            function __() { this.constructor = d; }
-            d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
-        };
-    })();
+    var nextId = Sequence.nextId;
     /**
      * Controlling groups of tweens
      *
      * Using the TWEEN singleton to manage your tweens can cause issues in large apps with many components.
-     * In these cases, you may want to create your own smaller groups of tween
+     * In these cases, you may want to create your own smaller groups of tweens.
      */
-    var Main = /** @class */ (function (_super) {
-        __extends(Main, _super);
-        function Main() {
-            var _this = _super !== null && _super.apply(this, arguments) || this;
-            _this.version = VERSION;
-            _this.now = NOW$1;
-            _this.Group = Group;
-            _this.Easing = Easing;
-            _this.Interpolation = Interpolation;
-            _this.nextId = Sequence.nextId;
-            _this.Tween = Tween;
-            return _this;
-        }
-        return Main;
-    }(Group));
-    var TWEEN = new Main();
+    var TWEEN = mainGroup;
+    // This is the best way to export things in a way that's compatible with both ES
+    // Modules and CommonJS, without build hacks, and so as not to break the
+    // existing API.
+    // https://github.com/rollup/rollup/issues/1961#issuecomment-423037881
+    var getAll = TWEEN.getAll.bind(TWEEN);
+    var removeAll = TWEEN.removeAll.bind(TWEEN);
+    var add = TWEEN.add.bind(TWEEN);
+    var remove = TWEEN.remove.bind(TWEEN);
+    var update = TWEEN.update.bind(TWEEN);
+    var exports$1 = {
+        Easing: Easing,
+        Group: Group,
+        Interpolation: Interpolation,
+        now: now$1,
+        Sequence: Sequence,
+        nextId: nextId,
+        Tween: Tween,
+        VERSION: VERSION,
+        getAll: getAll,
+        removeAll: removeAll,
+        add: add,
+        remove: remove,
+        update: update,
+    };
 
-    return TWEEN;
+    exports.Easing = Easing;
+    exports.Group = Group;
+    exports.Interpolation = Interpolation;
+    exports.Sequence = Sequence;
+    exports.Tween = Tween;
+    exports.VERSION = VERSION;
+    exports.add = add;
+    exports.default = exports$1;
+    exports.getAll = getAll;
+    exports.nextId = nextId;
+    exports.now = now$1;
+    exports.remove = remove;
+    exports.removeAll = removeAll;
+    exports.update = update;
+
+    Object.defineProperty(exports, '__esModule', { value: true });
 
 })));
diff --git a/package-lock.json b/package-lock.json
index 0ddc94b..6a6373d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
 	"name": "@tweenjs/tween.js",
-	"version": "18.6.0",
+	"version": "18.6.1",
 	"lockfileVersion": 1,
 	"requires": true,
 	"dependencies": {
diff --git a/package.json b/package.json
index d9eb3c2..d11b7c4 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
 	"name": "@tweenjs/tween.js",
 	"description": "Super simple, fast and easy to use tweening engine which incorporates optimised Robert Penner's equations.",
-	"version": "18.6.0",
+	"version": "18.6.1",
 	"main": "dist/tween.cjs.js",
 	"types": "dist/tween.d.ts",
 	"module": "dist/tween.esm.js",
diff --git a/src/Version.ts b/src/Version.ts
index 1c665d8..f1ccb12 100644
--- a/src/Version.ts
+++ b/src/Version.ts
@@ -1,2 +1,2 @@
-const VERSION = '18.6.0'
+const VERSION = '18.6.1'
 export default VERSION