Source: polyfills.js

  1. /*!
  2.  * Module Polyfills
  3.  */
  5. /**
  6.  * @namespace Polyfills
  7.  */
  9. const MODULE_NAME = 'Polyfills';
  13. //###[ IMPORTS ]########################################################################################################
  15. import {assert, hasValue, isFunction, orDefault} from './basic.js';
  16. import {createFetchRequest} from './requests.js';
  20. //###[ EXPORTS ]########################################################################################################
  22. /**
  23.  * @namespace Polyfills:polyfillFetch
  24.  */
  26. /**
  27.  * Polyfills window.fetch with a simple XMLHttpRequest-based implementation adapted from "unfetch", to provide
  28.  * basic functionality with a compatible signature while keeping the source as small as possible.
  29.  *
  30.  * This polyfill should cover most basic use cases, but for complex cases you might need to polyfill something more
  31.  * complete (for example Github's implementation: https://github.com/github/fetch).
  32.  *
  33.  * @param {?Boolean} [force=false] - if true, replaces a possibly present native implementation with the polyfill as well
  34.  *
  35.  * @memberof Polyfills:polyfillFetch
  36.  * @alias polyfillFetch
  37.  * @see https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch
  38.  * @see https://github.com/developit/unfetch
  39.  * @example
  40.  * polyfillFetch(true);
  41.  */
  42. export function polyfillFetch(force=false){
  43. 	force = orDefault(force, false, 'bool');
  45. 	if( force || !isFunction(window.fetch) ){
  46. 		window.fetch = function(url, options=null){
  47. 			return createFetchRequest(url, options).execute();
  48. 		};
  49. 	}
  50. }
  54. /**
  55.  * @namespace Polyfills:polyfillElementMatches
  56.  */
  58. /**
  59.  * Adds Element.matches support, if not already present in browser. Falls back to ms or mozilla implementations
  60.  * if necessary.
  61.  *
  62.  * @throws error if Element.matches is not supported
  63.  *
  64.  * @memberof Polyfills:polyfillElementMatches
  65.  * @alias polyfillElementMatches
  66.  * @see https://developer.mozilla.org/en-US/docs/Web/API/Element/matches
  67.  * @example
  68.  * polyfillElementMatches()
  69.  * => makes Element.prototype.matches available, if not already present
  70.  */
  71. export function polyfillElementMatches(){
  72. 	const __methodName__ = 'polyfillElementMatches';
  74. 	if( !Element.prototype.matches ){
  75. 		Element.prototype.matches = Element.prototype.msMatchesSelector
  76. 			?? Element.prototype.webkitMatchesSelector
  77. 			?? null
  78. 		;
  79. 	}
  81. 	assert(hasValue(Element.prototype.matches), `${MODULE_NAME}:${__methodName__} | browser does not support Element.matches`);
  82. }
  86. /**
  87.  * @namespace Polyfills:polyfillCustomEvent
  88.  */
  90. /**
  91.  * Adds CustomEvent support, if not already present in browser. Falls back to manual implementation via
  92.  * document.createEvent and event.initCustomEvent, if necessary.
  93.  *
  94.  * @memberof Polyfills:polyfillCustomEvent
  95.  * @alias polyfillCustomEvent
  96.  * @see https://developer.mozilla.org/en-US/docs/Web/API/CustomEvent/CustomEvent
  97.  * @example
  98.  * polyfillCustomEvent()
  99.  * => makes "window.CustomEvent" and "new CustomEvent()" available, if not already present
  100.  */
  101. export function polyfillCustomEvent(){
  102. 	if( isFunction(window.CustomEvent) ) return false;
  104. 	const CustomEvent = function(event, params){
  105. 		params = params ?? {bubbles : false, cancelable : false, detail : undefined};
  106. 		const e = document.createEvent('CustomEvent');
  107. 		e.initCustomEvent(event, params.bubbles, params.cancelable, params.detail);
  108. 		return e;
  109. 	};
  110. 	CustomEvent.prototype = window.Event.prototype;
  112. 	window.CustomEvent = CustomEvent;
  113. }
  117. /**
  118.  * @namespace Polyfills:polyfillArrayAt
  119.  */
  121. /**
  122.  * Adds support for Array.prototype.at, which is a fairly recent feature, compared to most other basic array
  123.  * operations, resulting in even modern Chrome, Firefox and Safari versions not having implemented this.
  124.  * But adding this is quite forward, it just being general array index access with possible negative index.
  125.  *
  126.  * @memberof Polyfills:polyfillArrayAt
  127.  * @alias polyfillArrayAt
  128.  * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/at
  129.  * @example
  130.  * polyfillArrayAt()
  131.  * => adds Array.prototype.at if not already defined
  132.  */
  133. export function polyfillArrayAt(){
  134. 	if( isFunction(Array.prototype.at) ) return false;
  136. 	Object.defineProperty(Array.prototype, 'at', {
  137. 		value : function(n){
  138. 			n = Math.trunc(n) || 0;
  139. 			if( n < 0 ) n += this.length;
  140. 			if( (n < 0) || (n >= this.length) ) return undefined;
  141. 			return this[n];
  142. 		},
  143. 		writable : true,
  144. 		enumerable : false,
  145. 		configurable : true
  146. 	});
  147. }