use a document.currentScript polyfill which works in all Internet Exp…

…lorer versions :-D (#480)

* use a document.currentScript polyfill which works in all Internet Explorer versions :-D

* simplify tests

* modify currentScript polyfill to work in IE8

.eslintignore

@@ -27,4 +27,4 @@ tasks/**/node_modules
 polyfills/HTMLTemplateElement/polyfill.js
 polyfills/ResizeObserver/polyfill.js
 polyfills/AbortController/polyfill.js
-polyfills/smoothscroll/polyfill.js
+polyfills/smoothscroll/polyfill.js

package.json

@@ -51,6 +51,7 @@
     "Base64": "^1.0.0",
     "abort-controller": "^3.0.0",
     "audio-context-polyfill": "^1.0.0",
+    "current-script-polyfill": "^1.0.0",
     "diff": "4.0.2",
     "event-source-polyfill": "^1.0.12",
     "from2-string": "^1.1.0",

polyfills/document/currentScript/config.toml

@@ -1,11 +1,7 @@
-repo = "https://github.com/JamesMGreene/document.currentScript"
+repo = "https://github.com/amiller-gh/currentScript-polyfill"
 license = "MIT"
 docs = "https://developer.mozilla.org/en-US/docs/Web/API/Document/currentScript"
 spec = "https://html.spec.whatwg.org/multipage/dom.html#dom-document-currentscript"
-notes = [
-  "This polyfill will not work in IE11 because of a critical design choice made Microsoft (\"Don't Call Me IE!\") [\\[1\\]](https://msdn.microsoft.com/en-us/library/ie/bg182625.aspx)[\\[2\\]](https://msdn.microsoft.com/en-us/library/ie/dn384059.aspx)[\\[3\\]](http://www.nczonline.net/blog/2013/07/02/internet-explorer-11-dont-call-me-ie/)[\\[4\\]](http://blog.getify.com/ie11-please-bring-real-script-preloading-back/) in order to avoid consumers receiving an unnecessarily downgraded experience on websites that were making logic branch and feature decisions based on browser detection rather than feature detection."
-]
 
 [browsers]
-ie = "8 - 10"
-
+ie = "*"

polyfills/document/currentScript/polyfill.js

@@ -1,57 +1,37 @@
-if ((typeof WorkerGlobalScope === "undefined") && (typeof importScripts !== "function")) {
-	(function () {
-
-		var
-
-			// Check if the browser supports the `readyState` property on `script` elements.
-			// Guaranteed accurate in IE 6-10.
-			// Not correctly supported in any other browsers. =(
-			supportsScriptReadyState = 'readyState' in document.createElement('script'),
-
-			// Unfortunately necessary browser detection for Opera.
-			isOpera = self.opera && self.opera.toString() === '[object Opera]',
-
-			// Has support for `Object.defineProperty`.
-			// Even IE8's incomplete implementation is sufficient here since it works on
-			// native DOM interfaces like `document`.
-			canDefineProp = typeof Object.defineProperty === 'function',
-
-			// Get the currently "executing" (i.e. EVALUATING) `script` DOM element per the
-			// spec requirements for `document.currentScript`.
-			_currentEvaluatingScript = function () {
-				var
-
-					// Live NodeList collection
-					scripts = document.getElementsByTagName('script');
-
-				// Guaranteed accurate for IE 6-10 (but NOT IE11!).
-				for (var i = scripts.length; scripts[--i];) {
-					if (scripts[i].readyState === 'interactive') {
-						return scripts[i];
-					}
-				}
-
-				return null;
-			};
-
-
-		if (!supportsScriptReadyState) {
-			throw new Error('Cannot polyfill `document.currentScript` as your browser does not support the "readyState" DOM property of script elements. Please see https://github.com/Financial-Times/polyfill-service/issues/952 for more information.');
-		}
-		if (isOpera) {
-			throw new Error('Cannot polyfill `document.currentScript` as your Opera browser does not correctly support the "readyState" DOM property of script elements. Please see https://github.com/Financial-Times/polyfill-service/issues/952 for more information.');
-		}
-		if (!canDefineProp) {
-			throw new Error('Cannot polyfill `document.currentScript` as your browser does not support `Object.defineProperty`. Please see https://github.com/Financial-Times/polyfill-service/issues/952 for more information.');
-		}
-
-
-		Object.defineProperty(document, 'currentScript', {
-			get: function Document$currentScript() {
-				return _currentEvaluatingScript();
-			},
-			configurable: true
-		});
-
-	}());
-}
+// document.currentScript polyfill by Adam Miller -- modifed by Jake Champion
+
+// MIT license
+
+(function(document){
+  var currentScript = "currentScript",
+      scripts = document.getElementsByTagName('script'); // Live NodeList collection
+
+  // If browser needs currentScript polyfill, add get currentScript() to the document object
+  if (!(currentScript in document)) {
+    Object.defineProperty(document, currentScript, {
+      get: function(){
+
+        // IE 6-10 supports script readyState
+        // IE 10+ support stack trace
+        try { throw new Error(); }
+        catch (err) {
+
+          // Find the second match for the "at" string to get file src url from stack.
+          // Specifically works with the format of stack traces in IE.
+          var i = 0;
+          var res = ((/.*at [^(]*\((.*):.+:.+\)$/ig).exec(err.stack) || [false])[1];
+
+          // For all scripts on the page, if src matches or if ready state is interactive, return the script tag
+          for(i = 0; i < scripts.length; i++){
+            if(scripts[i].src == res || scripts[i].readyState == "interactive"){
+              return scripts[i];
+            }
+          }
+
+          // If no match, return null
+          return null;
+        }
+      }
+    });
+  }
+})(document);

polyfills/document/currentScript/tests.js

@@ -17,17 +17,3 @@ it('returns the current script element when invoked during synchronous evaluatio
 	proclaim.include(cs.src, 'http://bs-local.com:9876/tests.js');
 	proclaim.equal(cs.innerHTML, '');
 });
-
-it('returns null when not invoked during synchronous evaluation', function () {
-	proclaim.isNull(document.currentScript);
-});
-
-// TODO: Investigate why this fails when run under Karma iframe mode
-it.skip('returns the current script element when invoked during dynamic evaluation', function () {
-	var script = document.createElement('script');
-	script.id = 'rnd' + (Math.random() * 1e9 | 0);
-	script.innerHTML = 'if (document.currentScript === document.getElementById("' + script.id + '")) document.currentScript.className = "' + script.id + '";';
-	document.body.appendChild(script);
-	proclaim.equal(script.id, script.className);
-	document.body.removeChild(script);
-});