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.get(code)
// foo.js.map

code = sourceMappingURL.set(code, "/other/file.js.map")
// !function(){...}();
// /*# sourceMappingURL=/other/file.js.map */

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

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

sourceMappingURL.get(code)
// null

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.get(code)

Returns the url of the sourceMappingURL comment in code. Returns null if there is no such comment. Note that the url can be the empty string and that both the empty string and null are falsy. Consider using if (url === null) {} rather than if (url) {} if you need to tell those two cases apart.

sourceMappingURL.set(code, url [, commentSyntax])

Updates the sourceMappingURL comment in code to use url. Creates such a comment if there is none. Returns the updated code.

The commentSyntax argument is optional. It is an array. The first element of it defines how a comment starts, while the second element defines how it ends. The default value is ["/*", " */"]. /**/ comments were chosen as default in favor of // comments, because ideally they work with both JavaScript and CSS. This way, you don’t have to think about what type of code you’re working with. However, Chrome sadly does not support /**/ comments in JavaScript. So currently, you need to use .set(code, url, ["//"]) for JavaScript that needs source map support in Chrome. A bug has been filed about this.

sourceMappingURL.remove(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.

sourceMappingURL.SourceMappingURL(commentSyntax)

Lets you create a new SourceMappingURL instance, using commentSyntax as default comment syntax for the set method.

For example, if you mainly work with JavaScript code that needs to have source map support in Chrome, you could use it like this:

var SourceMappingURL = require("source-map-url").SourceMappingURL
var sourceMappingURL = new SourceMappingURL(["//"])

License

The X11 (“MIT”) License.

Changelog

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.)