diff --git a/lib/mixins/annotations.js b/lib/mixins/annotations.js
index 0f5ca45..783a178 100644
--- a/lib/mixins/annotations.js
+++ b/lib/mixins/annotations.js
@@ -26,10 +26,7 @@ export default {
     return this;
   },
 
-  note(x, y, w, h, contents, options) {
-    if (options == null) {
-      options = {};
-    }
+  note(x, y, w, h, contents, options = {}) {
     options.Subtype = 'Text';
     options.Contents = new String(contents);
     options.Name = 'Comment';
@@ -39,10 +36,7 @@ export default {
     return this.annotate(x, y, w, h, options);
   },
 
-  link(x, y, w, h, url, options) {
-    if (options == null) {
-      options = {};
-    }
+  link(x, y, w, h, url, options = {}) {
     options.Subtype = 'Link';
 
     if (typeof url === 'number') {
@@ -69,20 +63,14 @@ export default {
     return this.annotate(x, y, w, h, options);
   },
 
-  _markup(x, y, w, h, options) {
-    if (options == null) {
-      options = {};
-    }
+  _markup(x, y, w, h, options = {}) {
     const [x1, y1, x2, y2] = this._convertRect(x, y, w, h);
     options.QuadPoints = [x1, y2, x2, y2, x1, y1, x2, y1];
     options.Contents = new String();
     return this.annotate(x, y, w, h, options);
   },
 
-  highlight(x, y, w, h, options) {
-    if (options == null) {
-      options = {};
-    }
+  highlight(x, y, w, h, options = {}) {
     options.Subtype = 'Highlight';
     if (options.color == null) {
       options.color = [241, 238, 148];
@@ -90,54 +78,36 @@ export default {
     return this._markup(x, y, w, h, options);
   },
 
-  underline(x, y, w, h, options) {
-    if (options == null) {
-      options = {};
-    }
+  underline(x, y, w, h, options = {}) {
     options.Subtype = 'Underline';
     return this._markup(x, y, w, h, options);
   },
 
-  strike(x, y, w, h, options) {
-    if (options == null) {
-      options = {};
-    }
+  strike(x, y, w, h, options = {}) {
     options.Subtype = 'StrikeOut';
     return this._markup(x, y, w, h, options);
   },
 
-  lineAnnotation(x1, y1, x2, y2, options) {
-    if (options == null) {
-      options = {};
-    }
+  lineAnnotation(x1, y1, x2, y2, options = {}) {
     options.Subtype = 'Line';
     options.Contents = new String();
     options.L = [x1, this.page.height - y1, x2, this.page.height - y2];
     return this.annotate(x1, y1, x2, y2, options);
   },
 
-  rectAnnotation(x, y, w, h, options) {
-    if (options == null) {
-      options = {};
-    }
+  rectAnnotation(x, y, w, h, options = {}) {
     options.Subtype = 'Square';
     options.Contents = new String();
     return this.annotate(x, y, w, h, options);
   },
 
-  ellipseAnnotation(x, y, w, h, options) {
-    if (options == null) {
-      options = {};
-    }
+  ellipseAnnotation(x, y, w, h, options = {}) {
     options.Subtype = 'Circle';
     options.Contents = new String();
     return this.annotate(x, y, w, h, options);
   },
 
-  textAnnotation(x, y, w, h, text, options) {
-    if (options == null) {
-      options = {};
-    }
+  textAnnotation(x, y, w, h, text, options = {}) {
     options.Subtype = 'FreeText';
     options.Contents = new String(text);
     options.DA = new String();
diff --git a/lib/mixins/images.js b/lib/mixins/images.js
index 021ad21..30ce126 100644
--- a/lib/mixins/images.js
+++ b/lib/mixins/images.js
@@ -6,11 +6,8 @@ export default {
     return (this._imageCount = 0);
   },
 
-  image(src, x, y, options) {
+  image(src, x, y, options = {}) {
     let bh, bp, bw, image, ip, left, left1;
-    if (options == null) {
-      options = {};
-    }
     if (typeof x === 'object') {
       options = x;
       x = null;
diff --git a/lib/mixins/text.js b/lib/mixins/text.js
index 1a00db2..d9a58c2 100644
--- a/lib/mixins/text.js
+++ b/lib/mixins/text.js
@@ -70,10 +70,7 @@ export default {
     return this._text(text, x, y, options, this._line);
   },
 
-  widthOfString(string, options) {
-    if (options == null) {
-      options = {};
-    }
+  widthOfString(string, options = {}) {
     return (
       this._font.widthOfString(string, this._fontSize, options.features) +
       (options.characterSpacing || 0) * (string.length - 1)
@@ -189,13 +186,7 @@ export default {
     return this;
   },
 
-  _initOptions(x, y, options) {
-    if (x == null) {
-      x = {};
-    }
-    if (options == null) {
-      options = {};
-    }
+  _initOptions(x = {}, y, options = {}) {
     if (typeof x === 'object') {
       options = x;
       x = null;
@@ -241,10 +232,7 @@ export default {
     return result;
   },
 
-  _line(text, options, wrapper) {
-    if (options == null) {
-      options = {};
-    }
+  _line(text, options = {}, wrapper) {
     this._fragment(text, this.x, this.y, options);
     const lineGap = options.lineGap || this._lineGap || 0;
 
diff --git a/lib/mixins/vector.js b/lib/mixins/vector.js
index 1c657e5..61dbac4 100644
--- a/lib/mixins/vector.js
+++ b/lib/mixins/vector.js
@@ -61,11 +61,8 @@ export default {
     return this.addContent(`${number(m)} M`);
   },
 
-  dash(length, options) {
+  dash(length, options = {}) {
     let phase;
-    if (options == null) {
-      options = {};
-    }
     if (length == null) {
       return this;
     }
@@ -308,11 +305,8 @@ export default {
     return this.transform(1, 0, 0, 1, x, y);
   },
 
-  rotate(angle, options) {
+  rotate(angle, options = {}) {
     let y;
-    if (options == null) {
-      options = {};
-    }
     const rad = (angle * Math.PI) / 180;
     const cos = Math.cos(rad);
     const sin = Math.sin(rad);
@@ -329,14 +323,11 @@ export default {
     return this.transform(cos, sin, -sin, cos, x, y);
   },
 
-  scale(xFactor, yFactor, options) {
+  scale(xFactor, yFactor, options = {}) {
     let y;
     if (yFactor == null) {
       yFactor = xFactor;
     }
-    if (options == null) {
-      options = {};
-    }
     if (typeof yFactor === 'object') {
       options = yFactor;
       yFactor = xFactor;
diff --git a/lib/outline.js b/lib/outline.js
index c0d0c8b..8dc709d 100644
--- a/lib/outline.js
+++ b/lib/outline.js
@@ -1,9 +1,6 @@
 class PDFOutline {
-  constructor(document, parent, title, dest, options) {
+  constructor(document, parent, title, dest, options = { expanded: false }) {
     this.document = document;
-    if (options == null) {
-      options = { expanded: false };
-    }
     this.options = options;
     this.outlineData = {};
 
@@ -23,10 +20,7 @@ class PDFOutline {
     this.children = [];
   }
 
-  addItem(title, options) {
-    if (options == null) {
-      options = { expanded: false };
-    }
+  addItem(title, options = { expanded: false }) {
     const result = new PDFOutline(
       this.document,
       this.dictionary,
diff --git a/lib/page.js b/lib/page.js
index 7dde532..9c2fe77 100644
--- a/lib/page.js
+++ b/lib/page.js
@@ -64,11 +64,8 @@ const SIZES = {
 };
 
 class PDFPage {
-  constructor(document, options) {
+  constructor(document, options = {}) {
     this.document = document;
-    if (options == null) {
-      options = {};
-    }
     this.size = options.size || 'letter';
     this.layout = options.layout || 'portrait';
 
diff --git a/lib/reference.js b/lib/reference.js
index 04b9485..7c20c61 100644
--- a/lib/reference.js
+++ b/lib/reference.js
@@ -8,13 +8,10 @@ import PDFAbstractReference from './abstract_reference';
 import PDFObject from './object';
 
 class PDFReference extends PDFAbstractReference {
-  constructor(document, id, data) {
+  constructor(document, id, data = {}) {
     super();
     this.document = document;
     this.id = id;
-    if (data == null) {
-      data = {};
-    }
     this.data = data;
     this.gen = 0;
     this.compress = this.document.compress && !this.data.Filter;