Overview

Tools for working with sourceMappingURL comments.

var sourceMappingURL = require("source-map-url")

var code = [
  "!function(){...}();",
  "/*# sourceMappingURL=foo.js.map */"
].join("\n")

sourceMappingURL.existsIn(code)
// true

sourceMappingURL.getFrom(code)
// foo.js.map

code = sourceMappingURL.insertBefore(code, "// License: MIT\n")
// !function(){...}();
// // License: MIT
// /*# sourceMappingURL=foo.js.map */

code = sourceMappingURL.removeFrom(code)
// !function(){...}();
// // License: MIT

sourceMappingURL.existsIn(code)
// false

sourceMappingURL.getFrom(code)
// null

code += "//# sourceMappingURL=/other/file.js.map"
// !function(){...}();
// // License: MIT
// //# sourceMappingURL=/other/file.js.map

Installation

• npm install source-map-url
• bower install source-map-url
• component install lydell/source-map-url

Works with CommonJS, AMD and browser globals, through UMD.

Usage

sourceMappingURL.getFrom(code)

Returns the url of the sourceMappingURL comment in code. Returns null if there is no such comment.

sourceMappingURL.existsIn(code)

Returns true if there is a sourceMappingURL comment in code, or false otherwise.

sourceMappingURL.removeFrom(code)

Removes the sourceMappingURL comment in code. Does nothing if there is no such comment. Returns the updated code.

sourceMappingURL.insertBefore(code, string)

Inserts string before the sourceMappingURL comment in code. Appends string to code if there is no such comment.

Lets you append something to a file without worrying about burying the sourceMappingURL comment (by keeping it at the end of the file).

sourceMappingURL.regex

The regex that is used to match sourceMappingURL comments. It matches both // and /**/ comments, thus supporting both JavaScript and CSS.

Tests

Start by running npm test, which lints the code and runs the test suite in Node.js.

To run the tests in a browser, run testling (npm install -g testling) or testling -u.

License

The X11 (“MIT”) License.

Version 0.4.1 (2021-02-01)

• Improved: The package is now about 50% smaller, by excluding unnecessary files. Thanks to Piotr Kuczynski (@pkuczynski)!

Version 0.4.0 (2015-11-12)

• Changed: sourceMappingURL comments used to be matched only when placed at the end of the script. However, since several commonly used JavaScript libraries do not follow this convention and all popular web browsers accept non-trailing comments, this has been revised.

  So now non-trailing SourceMappingURL comments are matched as well.

Version 0.3.0 (2014-08-16)

• Changed: sourceMappingURL comments used to be matched only if they appeared on their own line. However, the spec only says:

  The generated code may include a line at the end of the source, with the following form:

  //# sourceMappingURL=<url>

  So now they are matched also when they appear on the same line as code.

• Removed: The .set() method. I couldn’t decide how it should work considering the above change. Moreover, it was unnecessarily complex (and would have gotten worse) for very little gain. It is much easier to run .remove() if needed, and then simply code += "\n//# sourceMappingURL=" + url (using the appropriate comment syntax and newline). KISS.

• Changed: The .insertBefore() method now always inserts the string exactly before the sourceMappingURL comment; not before the newline before the comment (if any). Moreover, it does not ensure that the comment will be on a new line anymore. This is up to the caller. KISS.

• Changed: The .remove() method no longer removes the newline before the sourceMappingURL (if any).

• Changed: Renamed .get() to .getFrom().

• Changed: Renamed .remove() to .removeFrom().

• Added: The .existsIn() method.

Version 0.2.0 (2014-02-23)

• Changed: A space is no longer inserted before the closing comment syntax. If such a space is desired, it needs to be put in the closing comment syntax itself (such as ["/*", " */"] instead of ["/*", "*/"]). (Backwards incompatible change.)

Version 0.1.0 (2014-02-22)

• Initial release.