Add back polyfill

Author: mttwc

Diff for: src/oneNoteDataStructures/oneNoteItemUtils.ts

@@ -3,6 +3,9 @@ import { OneNoteItem } from './oneNoteItem';
 import { Section } from './section';
 import { SectionGroup } from './sectionGroup';
 import { SharedNotebook } from './sharedNotebook';
+import { Polyfills } from '../polyfills';
+
+Polyfills.find();
 
 export class OneNoteItemUtils {
 	/**

Diff for: src/polyfills.ts

@@ -0,0 +1,50 @@
+export module Polyfills {
+	// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/find?v=control
+	export function find() {
+		// https://tc39.github.io/ecma262/#sec-array.prototype.find
+		if (!Array.prototype.find) {
+			Object.defineProperty(Array.prototype, 'find', {
+				value: function (predicate) {
+					// 1. const O be ? ToObject(this value).
+					if (this == null) {
+						throw new TypeError('"this" is null or not defined');
+					}
+
+					var o = Object(this);
+
+					// 2. const len be ? ToLength(? Get(O, "length")).
+					// tslint:disable-next-line:no-bitwise
+					var len = o.length >>> 0;
+
+					// 3. If IsCallable(predicate) is false, throw a TypeError exception.
+					if (typeof predicate !== 'function') {
+						throw new TypeError('predicate must be a function');
+					}
+
+					// 4. If thisArg was supplied, const T be thisArg; else const T be undefined.
+					var thisArg = arguments[1];
+
+					// 5. const k be 0.
+					var k = 0;
+
+					// 6. Repeat, while k < len
+					while (k < len) {
+						// a. const Pk be ! ToString(k).
+						// b. const kValue be ? Get(O, Pk).
+						// c. const testResult be ToBoolean(? Call(predicate, T, « kValue, k, O »)).
+						// d. If testResult is true, return kValue.
+						var kValue = o[k];
+						if (predicate.call(thisArg, kValue, k, o)) {
+							return kValue;
+						}
+						// e. Increase k by 1.
+						k++;
+					}
+
+					// 7. Return undefined.
+					return undefined;
+				}
+			});
+		}
+	}
+}