Fix errors reported by TypeScript compiler

package.json

@@ -69,6 +69,8 @@
     "rollup-plugin-istanbul": "^2.0.1",
     "rollup-plugin-node-resolve": "^5.0.0",
     "rollup-plugin-terser": "^5.1.3",
+    "typedoc": "^0.16.9",
+    "typescript": "^3.7.5",
     "yargs": "^14.0.0"
   },
   "dependencies": {

src/core/core.animation.js

@@ -18,7 +18,6 @@ const interpolators = {
 
 class Animation {
 	constructor(cfg, target, prop, to) {
-		const me = this;
 		let from = cfg.from;
 
 		if (from === undefined) {
@@ -34,16 +33,16 @@ class Animation {
 			to = from;
 		}
 
-		me._active = true;
-		me._fn = cfg.fn || interpolators[cfg.type || typeof from];
-		me._easing = helpers.easing.effects[cfg.easing || 'linear'];
-		me._start = Math.floor(Date.now() + (cfg.delay || 0));
-		me._duration = Math.floor(cfg.duration);
-		me._loop = !!cfg.loop;
-		me._target = target;
-		me._prop = prop;
-		me._from = from;
-		me._to = to;
+		this._active = true;
+		this._fn = cfg.fn || interpolators[cfg.type || typeof from];
+		this._easing = helpers.easing.effects[cfg.easing || 'linear'];
+		this._start = Math.floor(Date.now() + (cfg.delay || 0));
+		this._duration = Math.floor(cfg.duration);
+		this._loop = !!cfg.loop;
+		this._target = target;
+		this._prop = prop;
+		this._from = from;
+		this._to = to;
 	}
 
 	active() {

src/core/core.animator.js

@@ -2,6 +2,10 @@
 
 import helpers from '../helpers';
 
+/**
+ * @typedef { import("./core.controller") } Chart
+ */
+
 function drawFPS(chart, count, date, lastDate) {
 	const fps = (1000 / (date - lastDate)) | 0;
 	const ctx = chart.ctx;
@@ -21,6 +25,7 @@ class Animator {
 		this._request = null;
 		this._charts = new Map();
 		this._running = false;
+		this._lastDate = undefined;
 	}
 
 	/**

src/core/core.controller.js

@@ -174,24 +174,35 @@ class Chart {
 
 		config = initConfig(config);
 		const initialCanvas = getCanvas(item);
-		me._initializePlatform(initialCanvas, config);
+		this.platform = me._initializePlatform(initialCanvas, config);
 
 		const context = me.platform.acquireContext(initialCanvas, config);
 		const canvas = context && context.canvas;
 		const height = canvas && canvas.height;
 		const width = canvas && canvas.width;
 
-		me.id = helpers.uid();
-		me.ctx = context;
-		me.canvas = canvas;
-		me.config = config;
-		me.width = width;
-		me.height = height;
-		me.aspectRatio = height ? width / height : null;
-		me.options = config.options;
-		me._bufferedRender = false;
-		me._layers = [];
-		me._metasets = [];
+		this.id = helpers.uid();
+		this.ctx = context;
+		this.canvas = canvas;
+		this.config = config;
+		this.width = width;
+		this.height = height;
+		this.aspectRatio = height ? width / height : null;
+		this.options = config.options;
+		this._bufferedRender = false;
+		this._layers = [];
+		this._metasets = [];
+		this.boxes = [];
+		this.currentDevicePixelRatio = undefined;
+		this.chartArea = undefined;
+		this.data = undefined;
+		this.active = undefined;
+		this.lastActive = undefined;
+		this._lastEvent = undefined;
+		this._listeners = {};
+		this._sortedMetasets = [];
+		this._updating = false;
+		this.scales = {};
 
 		// Add the chart instance to the global namespace
 		Chart.instances[me.id] = me;
@@ -250,17 +261,14 @@ class Chart {
 	 * @private
 	 */
 	_initializePlatform(canvas, config) {
-		const me = this;
-
 		if (config.platform) {
-			me.platform = new config.platform();
+			return new config.platform();
 		} else if (!isDomSupported()) {
-			me.platform = new BasicPlatform();
+			return new BasicPlatform();
 		} else if (window.OffscreenCanvas && canvas instanceof window.OffscreenCanvas) {
-			me.platform = new BasicPlatform();
-		} else {
-			me.platform = new DomPlatform();
+			return new BasicPlatform();
 		}
+		return new DomPlatform();
 	}
 
 	clear() {

src/core/core.element.js

@@ -5,12 +5,14 @@ import {isNumber} from '../helpers/helpers.math';
 
 class Element {
 
-	constructor(configuration) {
-		if (configuration) {
-			extend(this, configuration);
-		}
+	constructor(cfg) {
+		this.x = undefined;
+		this.y = undefined;
+		this.hidden = undefined;
 
-		// this.hidden = false; we assume Element has an attribute called hidden, but do not initialize to save memory
+		if (cfg) {
+			extend(this, cfg);
+		}
 	}
 
 	tooltipPosition() {

src/core/core.interaction.js

@@ -4,6 +4,10 @@ import helpers from '../helpers/index';
 import {_isPointInArea} from '../helpers/helpers.canvas';
 import {_lookup, _rlookup} from '../helpers/helpers.collection';
 
+/**
+ * @typedef { import("./core.controller") } Chart
+ */
+
 /**
  * Helper function to get relative position for an event
  * @param {Event|IEvent} e - The event to get the position for

src/core/core.layouts.js

@@ -3,6 +3,10 @@
 import defaults from './core.defaults';
 import helpers from '../helpers';
 
+/**
+ * @typedef { import("./core.controller") } Chart
+ */
+
 const extend = helpers.extend;
 
 const STATIC_POSITIONS = ['left', 'top', 'right', 'bottom'];