Turn on some TypeScript checks (#7116)

Turn on some TypeScript checks

src/controllers/controller.line.js

@@ -29,7 +29,7 @@ class LineController extends DatasetController {
 	constructor(chart, datasetIndex) {
 		super(chart, datasetIndex);
 
-		this._showLine = undefined;
+		this._showLine = false;
 	}
 
 	update(mode) {

src/core/core.controller.js

@@ -206,7 +206,8 @@ class Chart {
 		this.active = undefined;
 		this.lastActive = undefined;
 		this._lastEvent = undefined;
-		this._listeners = {resize: undefined};
+		/** @type {{resize?: function}} */
+		this._listeners = {};
 		this._sortedMetasets = [];
 		this._updating = false;
 		this.scales = {};

src/core/core.scale.js

@@ -6,6 +6,10 @@ import {_factorize, toDegrees, toRadians} from '../helpers/helpers.math';
 import {_parseFont, resolve, toPadding} from '../helpers/helpers.options';
 import Ticks from './core.ticks';
 
+/**
+ * @typedef { import("./core.controller").default } Chart
+ */
+
 defaults.set('scale', {
 	display: true,
 	offset: false,
@@ -227,10 +231,13 @@ class Scale extends Element {
 
 		/** @type {string} */
 		this.id = cfg.id;
+		/** @type {string} */
 		this.type = cfg.type;
 		/** @type {object} */
 		this.options = cfg.options;
+		/** @type {CanvasRenderingContext2D} */
 		this.ctx = cfg.ctx;
+		/** @type {Chart} */
 		this.chart = cfg.chart;
 
 		// implements box
@@ -273,26 +280,24 @@ class Scale extends Element {
 		this.min = undefined;
 		this.max = undefined;
 		/** @type {object[]} */
-		this.ticks = null;
+		this.ticks = [];
 		/** @type {object[]|null} */
 		this._gridLineItems = null;
 		/** @type {object[]|null} */
 		this._labelItems = null;
 		/** @type {object|null} */
 		this._labelSizes = null;
-		/** @type {number} */
-		this._length = undefined;
-		/** @type {object} */
+		this._length = 0;
 		this._longestTextCache = {};
 		/** @type {number} */
 		this._startPixel = undefined;
 		/** @type {number} */
 		this._endPixel = undefined;
-		this._reversePixels = undefined;
+		this._reversePixels = false;
 		this._userMax = undefined;
 		this._userMin = undefined;
-		this._ticksLength = undefined;
-		this._borderValue = undefined;
+		this._ticksLength = 0;
+		this._borderValue = 0;
 	}
 
 	/**
@@ -1418,7 +1423,9 @@ class Scale extends Element {
 		const position = options.position;
 		const isReverse = me.options.reverse;
 		let rotation = 0;
-		let scaleLabelX, scaleLabelY, textAlign;
+		/** @type CanvasTextAlign */
+		let textAlign;
+		let scaleLabelX, scaleLabelY;
 
 		if (me.isHorizontal()) {
 			switch (scaleLabelAlign) {

src/helpers/helpers.segment.js

@@ -190,6 +190,7 @@ function solidSegments(points, start, max, loop) {
 			if (!prev.skip) {
 				loop = false;
 				result.push({start: start % count, end: (end - 1) % count, loop});
+				// @ts-ignore
 				start = last = cur.stop ? end : null;
 			}
 		} else {

src/platform/platform.dom.js

@@ -42,7 +42,7 @@ const EVENT_TYPES = {
 function readUsedSize(element, property) {
 	const value = helpers.dom.getStyle(element, property);
 	const matches = value && value.match(/^(\d+)(\.\d+)?px$/);
-	return matches ? Number(matches[1]) : undefined;
+	return matches ? +matches[1] : undefined;
 }
 
 /**
@@ -110,19 +110,22 @@ function initCanvas(canvas, config) {
  * @private
  */
 const supportsEventListenerOptions = (function() {
-	let supports = false;
+	let passiveSupported = false;
 	try {
-		const options = Object.defineProperty({}, 'passive', {
-			// eslint-disable-next-line getter-return
-			get() {
-				supports = true;
+		const options = {
+			get passive() { // This function will be called when the browser attempts to access the passive property.
+				passiveSupported = true;
+				return false;
 			}
-		});
-		window.addEventListener('e', null, options);
+		};
+		// @ts-ignore
+		window.addEventListener('test', null, options);
+		// @ts-ignore
+		window.removeEventListener('test', null, options);
 	} catch (e) {
 		// continue regardless of error
 	}
-	return supports;
+	return passiveSupported;
 }());
 
 // Default passive to true as expected by Chrome for 'touchstart' and 'touchend' events.

src/scales/scale.category.js

@@ -8,12 +8,10 @@ class CategoryScale extends Scale {
 	constructor(cfg) {
 		super(cfg);
 
-		/** @type {number} */
-		this._numLabels = undefined;
+		this._numLabels = 0;
 		/** @type {number} */
 		this._startValue = undefined;
-		/** @type {number} */
-		this._valueRange = undefined;
+		this._valueRange = 0;
 	}
 
 	/**

src/scales/scale.linearbase.js

@@ -119,8 +119,7 @@ class LinearScaleBase extends Scale {
 		this._startValue = undefined;
 		/** @type {number} */
 		this._endValue = undefined;
-		/** @type {number} */
-		this._valueRange = undefined;
+		this._valueRange = 0;
 	}
 
 	/**

src/scales/scale.logarithmic.js

@@ -68,8 +68,7 @@ class LogarithmicScale extends Scale {
 		this.end = undefined;
 		/** @type {number} */
 		this._startValue = undefined;
-		/** @type {number} */
-		this._valueRange = undefined;
+		this._valueRange = 0;
 	}
 
 	/**

src/scales/scale.radialLinear.js

@@ -302,7 +302,7 @@ class RadialLinearScale extends LinearScaleBase {
 		/** @type {number} */
 		this.drawingArea = undefined;
 		/** @type {string[]} */
-		this.pointLabels = undefined;
+		this.pointLabels = [];
 	}
 
 	setDimensions() {

src/scales/scale.time.js

@@ -7,30 +7,31 @@ import {_lookup, _lookupByKey} from '../helpers/helpers.collection';
 
 /**
  * @typedef { import("../core/core.adapters").Unit } Unit
+ * @typedef {{common: boolean, size: number, steps?: number}} Interval
  */
 
 // Integer constants are from the ES6 spec.
 const MAX_INTEGER = Number.MAX_SAFE_INTEGER || 9007199254740991;
 
 /**
- * @type {Map<Unit, {common: boolean, size: number, steps?: number}>}
+ * @type {Object<Unit, Interval>}
  */
-const INTERVALS = new Map();
-INTERVALS.set('millisecond', {common: true, size: 1, steps: 1000});
-INTERVALS.set('second', {common: true, size: 1000, steps: 60});
-INTERVALS.set('minute', {common: true, size: 60000, steps: 60});
-INTERVALS.set('hour', {common: true, size: 3600000, steps: 24});
-INTERVALS.set('day', {common: true, size: 86400000, steps: 30});
-INTERVALS.set('week', {common: false, size: 604800000, steps: 4});
-INTERVALS.set('month', {common: true, size: 2.628e9, steps: 12});
-INTERVALS.set('quarter', {common: false, size: 7.884e9, steps: 4});
-INTERVALS.set('year', {common: true, size: 3.154e10});
+const INTERVALS = {
+	millisecond: {common: true, size: 1, steps: 1000},
+	second: {common: true, size: 1000, steps: 60},
+	minute: {common: true, size: 60000, steps: 60},
+	hour: {common: true, size: 3600000, steps: 24},
+	day: {common: true, size: 86400000, steps: 30},
+	week: {common: false, size: 604800000, steps: 4},
+	month: {common: true, size: 2.628e9, steps: 12},
+	quarter: {common: false, size: 7.884e9, steps: 4},
+	year: {common: true, size: 3.154e10}
+};
 
 /**
  * @type {Unit[]}
  */
-const UNITS = [];
-INTERVALS.forEach((v, k) => UNITS.push(k));
+const UNITS = /** @type Unit[] */(Object.keys(INTERVALS));
 
 /**
  * @param {number} a
@@ -60,7 +61,7 @@ function arrayUnique(items) {
 
 /**
  * @param {TimeScale} scale
- * {*} input
+ * @param {*} input
  */
 function parse(scale, input) {
 	if (isNullOrUndef(input)) {
@@ -256,11 +257,10 @@ function interpolate(table, skey, sval, tkey) {
  */
 function determineUnitForAutoTicks(minUnit, min, max, capacity) {
 	const ilen = UNITS.length;
-	let i, interval, factor;
 
-	for (i = UNITS.indexOf(minUnit); i < ilen - 1; ++i) {
-		interval = INTERVALS.get(UNITS[i]);
-		factor = interval.steps ? interval.steps : MAX_INTEGER;
+	for (let i = UNITS.indexOf(minUnit); i < ilen - 1; ++i) {
+		const interval = INTERVALS[UNITS[i]];
+		const factor = interval.steps ? interval.steps : MAX_INTEGER;
 
 		if (interval.common && Math.ceil((max - min) / (factor * interval.size)) <= capacity) {
 			return UNITS[i];
@@ -282,7 +282,7 @@ function determineUnitForAutoTicks(minUnit, min, max, capacity) {
 function determineUnitForFormatting(scale, numTicks, minUnit, min, max) {
 	for (let i = UNITS.length - 1; i >= UNITS.indexOf(minUnit); i--) {
 		const unit = UNITS[i];
-		if (INTERVALS.get(unit).common && scale._adapter.diff(max, min, unit) >= numTicks - 1) {
+		if (INTERVALS[unit].common && scale._adapter.diff(max, min, unit) >= numTicks - 1) {
 			return unit;
 		}
 	}
@@ -296,7 +296,7 @@ function determineUnitForFormatting(scale, numTicks, minUnit, min, max) {
  */
 function determineMajorUnit(unit) {
 	for (let i = UNITS.indexOf(unit) + 1, ilen = UNITS.length; i < ilen; ++i) {
-		if (INTERVALS.get(UNITS[i]).common) {
+		if (INTERVALS[UNITS[i]].common) {
 			return UNITS[i];
 		}
 	}
@@ -438,6 +438,7 @@ function setMajorTicks(scale, ticks, map, majorUnit) {
  */
 function ticksFromTimestamps(scale, values, majorUnit) {
 	const ticks = [];
+	/** @type {Object<number,object>} */
 	const map = {};
 	const ilen = values.length;
 	let i, value;
@@ -575,7 +576,7 @@ class TimeScale extends Scale {
 		const time = options.time || (options.time = {});
 		const adapter = this._adapter = new adapters._date(options.adapters.date);
 
-
+		/** @type {{data: number[], labels: number[], all: number[]}} */
 		this._cache = {
 			data: [],
 			labels: [],
@@ -584,7 +585,7 @@ class TimeScale extends Scale {
 
 		/** @type {Unit} */
 		this._unit = 'day';
-		/** @type {Unit | undefined} */
+		/** @type {Unit=} */
 		this._majorUnit = undefined;
 		/** @type {object} */
 		this._offsets = {};

tsconfig.json

@@ -5,7 +5,10 @@
     "allowSyntheticDefaultImports": true,
     "allowJs": true,
     "checkJs": true,
-    "noEmit": true
+    "noEmit": true,
+    "alwaysStrict": true,
+    "strictBindCallApply": true,
+    "strictFunctionTypes": true
   },
   "typedocOptions": {
     "name": "Chart.js",