source-map-url

What is source-map-url?

The source-map-url npm package is a utility for working with source map URLs. It allows you to extract, insert, or remove source map URLs within a file, typically JavaScript or CSS files. This can be useful for developers who need to manage source map links in their generated code.

What are source-map-url's main functionalities?

Extracting source map URL

This feature allows you to extract the source map URL from a string of code. The `getFrom` method returns the URL if it exists.

const sourceMapUrl = require('source-map-url');
const code = '/*# sourceMappingURL=/path/to/file.js.map */';
const extractedUrl = sourceMapUrl.getFrom(code);

Inserting source map URL

This feature enables you to insert a source map URL into a string of code. The `insertInto` method adds the specified URL at the end of the code.

const sourceMapUrl = require('source-map-url');
const code = 'function example() {}';
const newCode = sourceMapUrl.insertInto(code, '/path/to/file.js.map');

Removing source map URL

This feature is used to remove an existing source map URL from a string of code. The `removeFrom` method strips out the source map URL.

const sourceMapUrl = require('source-map-url');
const code = 'function example() {}\n/*# sourceMappingURL=/path/to/file.js.map */';
const newCode = sourceMapUrl.removeFrom(code);

Other packages similar to source-map-url

source-map

The 'source-map' package provides utilities for generating and consuming source maps. It is more feature-rich than 'source-map-url', offering functionality for creating, parsing, and manipulating source maps in addition to handling URLs.

convert-source-map

The 'convert-source-map' package is similar to 'source-map-url' but with additional capabilities for converting source maps between different formats, such as from inline to external or vice versa.

README

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 breaking the sourceMappingURL comment (which needs to be 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.

Changelog

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.