Hi Frederik (or other reviewers),

the failed test only complains that the commit message (in my forked repository) does not adhere to the required format. Can this can be resolved when the pull request is merged? Apart from this, the code changes seem to pass the tests. Let me know if you require something else from me.

Can this can be resolved when the pull request is merged?

Commit message can be changed using interactive rebase.

Regarding the effecting change this creates,@gkalpak or@Narretz will have to review it. I only wanted to mention the usage ofbind looked incorrect.

function sayHello() {  console.log("hi");}sayHello();sayHello.bind(window); // does NOT execute sayHello(), bind returns a method which is still supposed to be executed by invoking the returned function.sayHello.call(window); // does execute sayHello()

Under which circumstances does this happen? It's reported like it happens always but this seems unlikely.

We need a test or at least a reproduction that shows the error.

I had difficulties isolating the problem as requested. In particular, I still do not understand the difference in Firefox and Chromium behavior. I suggest to let this pull request rest until I know better what is going on on my particular system. Thanks to the reviewers anyway—this is not as easy as I thought initially.

I am reopening this pull request with a minimal example to reliably reproduce the error that this pull request fixes.

I constructed a minimal browser extension in the directorytest/extension. (Note: this is for testing/demonstration only. This addition is not meant to be merged with the main repository.) The extension adds the text “Hello!” to the Google logo onhttps://www.google.ch.

Instructions:

• Create a local copy of angular.js intest/extension. Eg., download fromhttp://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.js.
• Test on Chromium: Go to “More tools” → “Extensions” → “Load unpackaged extension...” and choose the directorytest/extension.
• Openhttps://www.google.ch. If the extension is properly loaded, the message “Hello!” appears on top of the Google logo.
• Check the Javascript console: no error.
• Test on Firefox: Enter “about:debugging” in the address bar, click “Load Temporary Add-on”, and again choose the directorytest/extension.
• Openhttps://www.google.ch. If the extension is properly loaded, the message “Hello!” appears on top of the Google logo.
• Check the Javascript console:TypeError: 'requestAnimationFrame' called on an object that does not implement interface Window.

This error vanishes with the changes tosrc/ng/raf.js in the pull request.

I am still not sure what exactly the difference between Firefox and Chromium is. Here is my current guess: it seems as if in Firefox, there are two different functionswindow.requestAnimationFrame and the globalrequestAnimationFrame. In Chromium, both identifiers seem to reference the same function.

Try it yourself: edit angular.js locally and insert the following function definition:

function compareRAF($window) {  var rafWindow = $window.requestAnimationFrame;  var rafGlobal = requestAnimationFrame;  console.log("equal:", rafWindow == rafGlobal);}

Then, insertcompareRAF($window) at the beginning of$$RAFProvider() as follows:

function $$RAFProvider() { //rAF  this.$get = ['$window', '$timeout', function($window, $timeout) {    compareRAF($window);    var requestAnimationFrame = ...

Now test the extension in both browsers as described above. Firefox reportsequal: false, while Chromium printsequal: true.

Does this give anyone insight into theTypeError in Firefox?

I tried to reproduce, but couldn't get the extension to work on Firefox 55. Can you?

Yes, I can get it to work in Firefox 55.0.2 (64-bit). Did you place a copy ofangular.js intest/extension? Here is how it looks like on my computer:

I am using Firefox 55.0.3 (64-bit) (on Windows 10) and I can't get the temp extension to load when I include the angular.js file incontent_scripts[0].js array:

"//":"This works""content_scripts": [  {"matches": ["..."],"js": ["test.js"    ]  }]"//":"This doesn't :(""content_scripts": [  {"matches": ["..."],"js": ["test.js","angular.js"    ]  }]

But I was able to reproduce the problem withrequestAnimationFrame in Firefox extensions. All you need is:

// test.jsvarraf1=requestAnimationFrame;varraf2=window.requestAnimationFrame;console.log(raf1===raf2);// falseraf1(()=>console.log(1));// Worksraf2(()=>console.log(2));// TypeError: 'requestAnimationFrame' called on an object that does not implement interface Window.

I also tried with Firefox Nightly and it still doesn't work, although there is no error logged to the console 😕

TBH, this sounds like a bug in Firefox. I wonder what else might be affected (besidesrequestAnimationFrame) - if any.@dmuellner, could you file a bug report for Firefox and post the link here?

Hi@gkalpak,

(1) the demo extension works for me in Firefox 55.0.3 (32-bit) on Windows 10. However, since you are able to reproduce the problem without angular.js, let's not worry about this.

(2) If you don't see the error logged on the (primary) console, try the “Debug” button in Firefox's “about:debugging” page. This opens a second console, on which you will likely see the error message.

(3) I don't think that this is a bug in Firefox but I suspect that this is intended behavior. Let me know if you feel I should still report this to the Firefox community. Here are my arguments:

The error is due to the question what the global object is in the JavaScript scope whenrequestAnimationFrame is called. In a web browser, in a script on an HTML page, the global object is the globalWindow. Your example code

var raf1 = requestAnimationFrame;var raf2 = window.requestAnimationFrame;console.log(raf1 === raf2);

reportstrue if the JavaScript code is part of a normal<script> section.

However, if the JavaScript code is executed as part of an extension, the global object is not necessarily the globalWindow. Reference:https://developer.mozilla.org/en-US/docs/Glossary/Global_object. Apparently, Firefox and Chrome differ here: it seems that the global object is still aWindow instance in Chrome but not in Firefox. The developer page referenced above does not explicitly mention browser extensions but is very clear that the global object is not always aWindow.

To me, the sanest solution is to bind therequestAnimationFrame reference to theWindow instance it was originally taken from. We do have aWindow instance when the method reference is generated:

var requestAnimationFrame = $window.requestAnimationFrame ||                            $window.webkitRequestAnimationFrame;

so we should callrequestAnimationFrame (ie., the variable of the same name) on$window itself and not on the global object (of unspecified type).

(1) the demo extension works for me in Firefox 55.0.3 (32-bit) on Windows 10. However, since you are able to reproduce the problem without angular.js, let's not worry about this.

¯\_(ツ)_/¯

(2) If you don't see the error logged on the (primary) console, try the “Debug” button in Firefox's “about:debugging” page. This opens a second console, on which you will likely see the error message.

Like I said, I do see the error in Firefox 55. I don't see it in Firefox Nightly.

(3) I don't think that this is a bug in Firefox but I suspect that this is intended behavior. Let me know if you feel I should still report this to the Firefox community. Here are my arguments:
...

I still think this is a bug in Firefox. When calling a function previously assign to a variable (when in strict mode as we are here), it should run withthis === undefined and notthis === <global object> (as happens in non-strict mode.

Also, the following will work in a normal (non-extension) environment in Firefox:

varraf1=requestAnimationFrame;varraf2=window.requestAnimationFrame;raf1(cb);raf1.call(undefined,cb);raf1.call(null,cb);raf1.call(this,cb);raf2(cb);raf2.call(undefined,cb);raf2.call(null,cb);raf2.call(window,cb);

From the above, only the last one works from an extension. IMO, this is a clear indication that something is wrong. I am fine working aroung this in AngularJS (as you suggested) - it won't be the first time we work around browser-specific bugs - but I would still report it to Firefox and see what they think.