file is being assigned a //# sourceMappingURL but already has one

Question

I just notice Firefox console outputs the following error for every single .js/.coffee file in my project (even the packages).

-file- is being assigned a //# sourceMappingURL, but already has one

Chrome's console doesn't show anything. I tried deleting all the .map files and clearing Firefox's cache but I'm still getting the errors.

I'm seeing the same thing. Did a search and found this SO question, asked only an hour prior :-) BTW, this is on FF 27. — nilskp, Feb 13 '14 at 18:13
Seems to be a firefox bug: [925614](https://bugzilla.mozilla.org/show_bug.cgi?id=925614). But it's a warning, not an error. Look for other error messages if your code isn't working. — DS., Feb 14 '14 at 19:56
@DS. - thanks for mentioning it was a warning. It's unhelpful that the message starts 'Error: ....' in addition to being a bug already — Wandering Zombie, Mar 08 '14 at 23:29
It appears even in latest Firefox 29 beta-5 and jQuery 1.10.2 .. switched to 1.11.0 it gone. — hsobhy, Apr 07 '14 at 08:09

Ich · Accepted Answer · 2016-03-24T13:26:20.400

20

It's a warning (not an error) and it is a bug (~~https://bugzilla.mozilla.org/show_bug.cgi?id=1020846~~ fixed in FF 33)

This warning/error also applies to other libs (angular, backbone, etc.)

edited Mar 24 '16 at 13:26

answered Jun 19 '14 at 09:50

Ich

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According to the linked bug this is fixed in firefox 32, 33. – surfmuggle Dec 03 '14 at 14:44

score 7 · Answer 2 · answered Mar 14 '14 at 23:25

7

I have been working on a project for over a year now, I have never seen this message until roughly the last Firefox update.

I received it using jQuery 1.9.x, so I just updated my jQuery to 1.11.x and the error went away. I am now happy.

So, if you are using jQuery and see this Error/Warning, try updating your jQuery to the latest version.

Hope this helps someone.

answered Mar 14 '14 at 23:25

David V.F. Burton

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For me this was `` – Dan Jun 10 '14 at 13:32

score 7 · Answer 3 · answered Mar 15 '14 at 01:12

7

In Firefox 27.0.1 I was getting this exact same error. I already have jQuery 1.11.0.

SyntaxError: Using //@ to indicate sourceMappingURL pragmas is deprecated.
Use //# instead kendo.dataviz.min.js:25
22:09:26.635 Error: http://localhost/project/Scripts/kendo.dataviz.min.js is being assigned a //# sourceMappingURL, but already has one

I opened the kendo.dataviz.min.js and deleted the offending line:

//@ sourceMappingURL=kendo.dataviz.min.js.map

answered Mar 15 '14 at 01:12

Leniel Maccaferri

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This is a different error, and you can fix it by just replacing "@" with "#" – peterflynn Aug 30 '14 at 00:34

score 5 · Answer 4 · answered May 09 '14 at 10:31

5

put your code inside

   $( document ).ready(function() {
   //whatever
   });

then the message dissappears.

answered May 09 '14 at 10:31

raschid

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I think that is not always acceptable and since it is not webdev's code problem, it's not really them who should fix it. – userfuser Sep 01 '14 at 09:39

score 3 · Answer 5 · answered Apr 03 '14 at 15:35

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For the people using Visual Studio 2013, and have downloaded the jQuery libraries via NuGet, check your jquery-x.x.x.min.js and you'll find the text comment below that's popping this warning on Firefox.

// # sourceMappingURL=jquery-x.x.x.min.map

You can safely remove those lines.

answered Apr 03 '14 at 15:35

emerson.marini

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This did it for me in jQuery and FullPageJS. – lowtechsun Feb 23 '16 at 21:15

score 0 · Answer 6 · answered Apr 22 '14 at 12:28

Update jquery - from the jQuery website http://www.jquery.com/download

You can also download a sourcemap file for use when debugging with a compressed file. The map file is not required for users to run jQuery, it just improves the developer's debugger experience. As of jQuery 1.11.0/2.1.0 the //# sourceMappingURL comment is not included in the compressed file.

file is being assigned a //# sourceMappingURL but already has one

6 Answers6

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