[WIP] feat(core): add -noPolyfill option to grunt build

Gruntfile.js

@@ -83,7 +83,7 @@ module.exports = function(grunt) {
 					{
 						expand: true,
 						cwd: 'lib/core',
-						src: ['**/*.js', '!imports/index.js'],
+						src: ['**/*.js', '!imports/index.js', '!polyfills/index.js'],
 						dest: 'tmp/core'
 					}
 				]
@@ -350,6 +350,10 @@ module.exports = function(grunt) {
 				cmd: 'node',
 				args: ['./build/imports-generator']
 			},
+			npm_run_polyfills: {
+				cmd: 'node',
+				args: ['./build/polyfills-generator']
+			},
 			npm_run_testHeadless: {
 				cmd: 'npm',
 				args: ['run', 'test:headless']
@@ -363,7 +367,11 @@ module.exports = function(grunt) {
 		'concat:commons',
 		'add-locale'
 	]);
-	grunt.registerTask('pre-build', ['clean', 'run:npm_run_imports']);
+	const preBuildTasks = ['clean', 'run:npm_run_imports'];
+	if (!grunt.option('noPolyfills')) {
+		preBuildTasks.push('run:npm_run_polyfills');
+	}
+	grunt.registerTask('pre-build', preBuildTasks);
 	grunt.registerTask('build', [
 		'pre-build',
 		'validate',

README.md

@@ -140,6 +140,10 @@ Read the [documentation on contributing](CONTRIBUTING.md)
 
 [List of projects using axe-core](doc/projects.md)
 
+## Version Without Polyfills
+
+To build a version of axe without polyfills, run `grunt --noPolyfills`.
+
 ## Acknowledgements
 
 Thanks to Dulin Marat for his [css-selector-parser](https://www.npmjs.com/package/css-selector-parser) implementation which is included for shadow DOM support.

build/polyfills-generator.js

@@ -0,0 +1,39 @@
+const path = require('path');
+const browserify = require('browserify');
+const derequire = require('derequire');
+const createFile = require('./shared/create-file');
+
+const inputFile = path.join(
+	__dirname,
+	'..',
+	'lib',
+	'core',
+	'polyfills',
+	'index.js'
+);
+const outputFile = path.join(
+	__dirname,
+	'..',
+	'tmp',
+	'core',
+	'polyfills',
+	'index.js'
+);
+
+async function run() {
+	browserify(inputFile).bundle(async (err, result) => {
+		if (err) {
+			throw new Error('Cannot browserify polyfills', err);
+		}
+		try {
+			// Replace `require` calls with `_dereq_` in order not to confuse Cypress.js
+			result = derequire(result);
+			await createFile(outputFile, result);
+		} catch (error) {
+			throw new Error('Cannot write browserify generated polyfills', error);
+		}
+	});
+}
+
+// exec
+run();

lib/core/imports/index.js

@@ -6,36 +6,6 @@
  * See - './build/imports-generator'
  */
 
-/**
- * Polyfill `Promise`
- * Reference: https://www.npmjs.com/package/es6-promise
- */
-if (!('Promise' in window)) {
-	require('es6-promise').polyfill();
-}
-
-/**
- * Polyfill required TypedArray and functions
- * Reference https://github.com/zloirock/core-js/
- */
-if (!('Uint32Array' in window)) {
-	require('core-js/features/typed-array/uint32-array');
-}
-if (window.Uint32Array) {
-	if (!('some' in window.Uint32Array.prototype)) {
-		require('core-js/features/typed-array/some');
-	}
-	if (!('reduce' in window.Uint32Array.prototype)) {
-		require('core-js/features/typed-array/reduce');
-	}
-}
-
-/**
- * Polyfill `WeakMap`
- * Reference: https://github.com/polygonplanet/weakmap-polyfill
- */
-require('weakmap-polyfill');
-
 /**
  * Namespace `axe.imports` which holds required external dependencies
  *

lib/core/polyfills/index.js

@@ -0,0 +1,262 @@
+/**
+ * Note:
+ * This file is run via browserify to pull in the required dependencies.
+ * See - './build/polyfills-generator'
+ */
+
+/**
+ * Polyfill `Promise`
+ * Reference: https://www.npmjs.com/package/es6-promise
+ */
+if (!('Promise' in window)) {
+	require('es6-promise').polyfill();
+}
+
+/**
+ * Polyfill required TypedArray and functions
+ * Reference https://github.com/zloirock/core-js/
+ */
+if (!('Uint32Array' in window)) {
+	require('core-js/features/typed-array/uint32-array');
+}
+if (window.Uint32Array) {
+	if (!('some' in window.Uint32Array.prototype)) {
+		require('core-js/features/typed-array/some');
+	}
+	if (!('reduce' in window.Uint32Array.prototype)) {
+		require('core-js/features/typed-array/reduce');
+	}
+}
+
+/**
+ * Polyfill `WeakMap`
+ * Reference: https://github.com/polygonplanet/weakmap-polyfill
+ */
+require('weakmap-polyfill');
+
+/* eslint-disable */
+/*
+ These pollyfills came directly from the ES Specification it's self
+ Contained within:
+  - Object.assign
+  - Array.prototype.find
+*/
+if (typeof Object.assign !== 'function') {
+	(function() {
+		Object.assign = function(target) {
+			'use strict';
+			if (target === undefined || target === null) {
+				throw new TypeError('Cannot convert undefined or null to object');
+			}
+
+			var output = Object(target);
+			for (var index = 1; index < arguments.length; index++) {
+				var source = arguments[index];
+				if (source !== undefined && source !== null) {
+					for (var nextKey in source) {
+						if (source.hasOwnProperty(nextKey)) {
+							output[nextKey] = source[nextKey];
+						}
+					}
+				}
+			}
+			return output;
+		};
+	})();
+}
+
+if (!Array.prototype.find) {
+	Object.defineProperty(Array.prototype, 'find', {
+		value: function(predicate) {
+			if (this === null) {
+				throw new TypeError('Array.prototype.find called on null or undefined');
+			}
+			if (typeof predicate !== 'function') {
+				throw new TypeError('predicate must be a function');
+			}
+			var list = Object(this);
+			var length = list.length >>> 0;
+			var thisArg = arguments[1];
+			var value;
+
+			for (var i = 0; i < length; i++) {
+				value = list[i];
+				if (predicate.call(thisArg, value, i, list)) {
+					return value;
+				}
+			}
+			return undefined;
+		}
+	});
+}
+
+if (!Array.prototype.includes) {
+	Object.defineProperty(Array.prototype, 'includes', {
+		value: function(searchElement) {
+			'use strict';
+			var O = Object(this);
+			var len = parseInt(O.length, 10) || 0;
+			if (len === 0) {
+				return false;
+			}
+			var n = parseInt(arguments[1], 10) || 0;
+			var k;
+			if (n >= 0) {
+				k = n;
+			} else {
+				k = len + n;
+				if (k < 0) {
+					k = 0;
+				}
+			}
+			var currentElement;
+			while (k < len) {
+				currentElement = O[k];
+				if (
+					searchElement === currentElement ||
+					(searchElement !== searchElement && currentElement !== currentElement)
+				) {
+					// NaN !== NaN
+					return true;
+				}
+				k++;
+			}
+			return false;
+		}
+	});
+}
+
+// Production steps of ECMA-262, Edition 5, 15.4.4.17
+// Reference: http://es5.github.io/#x15.4.4.17
+if (!Array.prototype.some) {
+	Object.defineProperty(Array.prototype, 'some', {
+		value: function(fun) {
+			'use strict';
+
+			if (this == null) {
+				throw new TypeError('Array.prototype.some called on null or undefined');
+			}
+
+			if (typeof fun !== 'function') {
+				throw new TypeError();
+			}
+
+			var t = Object(this);
+			var len = t.length >>> 0;
+
+			var thisArg = arguments.length >= 2 ? arguments[1] : void 0;
+			for (var i = 0; i < len; i++) {
+				if (i in t && fun.call(thisArg, t[i], i, t)) {
+					return true;
+				}
+			}
+
+			return false;
+		}
+	});
+}
+
+if (!Array.from) {
+	Object.defineProperty(Array, 'from', {
+		value: (function() {
+			var toStr = Object.prototype.toString;
+			var isCallable = function(fn) {
+				return (
+					typeof fn === 'function' || toStr.call(fn) === '[object Function]'
+				);
+			};
+			var toInteger = function(value) {
+				var number = Number(value);
+				if (isNaN(number)) {
+					return 0;
+				}
+				if (number === 0 || !isFinite(number)) {
+					return number;
+				}
+				return (number > 0 ? 1 : -1) * Math.floor(Math.abs(number));
+			};
+			var maxSafeInteger = Math.pow(2, 53) - 1;
+			var toLength = function(value) {
+				var len = toInteger(value);
+				return Math.min(Math.max(len, 0), maxSafeInteger);
+			};
+
+			// The length property of the from method is 1.
+			return function from(arrayLike /*, mapFn, thisArg */) {
+				// 1. Let C be the this value.
+				var C = this;
+
+				// 2. Let items be ToObject(arrayLike).
+				var items = Object(arrayLike);
+
+				// 3. ReturnIfAbrupt(items).
+				if (arrayLike == null) {
+					throw new TypeError(
+						'Array.from requires an array-like object - not null or undefined'
+					);
+				}
+
+				// 4. If mapfn is undefined, then let mapping be false.
+				var mapFn = arguments.length > 1 ? arguments[1] : void undefined;
+				var T;
+				if (typeof mapFn !== 'undefined') {
+					// 5. else
+					// 5. a If IsCallable(mapfn) is false, throw a TypeError exception.
+					if (!isCallable(mapFn)) {
+						throw new TypeError(
+							'Array.from: when provided, the second argument must be a function'
+						);
+					}
+
+					// 5. b. If thisArg was supplied, let T be thisArg; else let T be undefined.
+					if (arguments.length > 2) {
+						T = arguments[2];
+					}
+				}
+
+				// 10. Let lenValue be Get(items, "length").
+				// 11. Let len be ToLength(lenValue).
+				var len = toLength(items.length);
+
+				// 13. If IsConstructor(C) is true, then
+				// 13. a. Let A be the result of calling the [[Construct]] internal method of C with an argument list containing the single item len.
+				// 14. a. Else, Let A be ArrayCreate(len).
+				var A = isCallable(C) ? Object(new C(len)) : new Array(len);
+
+				// 16. Let k be 0.
+				var k = 0;
+				// 17. Repeat, while k < len… (also steps a - h)
+				var kValue;
+				while (k < len) {
+					kValue = items[k];
+					if (mapFn) {
+						A[k] =
+							typeof T === 'undefined'
+								? mapFn(kValue, k)
+								: mapFn.call(T, kValue, k);
+					} else {
+						A[k] = kValue;
+					}
+					k += 1;
+				}
+				// 18. Let putStatus be Put(A, "length", len, true).
+				A.length = len;
+				// 20. Return A.
+				return A;
+			};
+		})()
+	});
+}
+
+if (!String.prototype.includes) {
+	String.prototype.includes = function(search, start) {
+		if (typeof start !== 'number') {
+			start = 0;
+		}
+		if (start + search.length > this.length) {
+			return false;
+		} else {
+			return this.indexOf(search, start) !== -1;
+		}
+	};
+}