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

Message

JavaScript
Warning: -file- is being assigned a //# sourceMappingURL, but already has one.

Error type

A warning. JavaScript execution won't be halted.

What went wrong?

A source map has been specified more than once for a given JavaScript source.

JavaScript sources are often combined and minified to make delivering them from the server more efficient. With source maps, the debugger can map the code being executed to the original source files. There are two ways to assign a source map, either by using a comment or by setting a header to the JavaScript file.

Examples

Setting a source map by using a comment in the file:

JavaScript
//# sourceMappingURL=http://example.com/path/to/your/sourcemap.map

Or, alternatively, you can set a header to your JavaScript file:

JavaScript
X-SourceMap: /path/to/file.js.map

See also

License

© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/javascript/reference/errors/already_has_pragma

Errors JavaScript Source maps Warning