convert-source-map #

Converts a source-map from/to different formats and allows adding/changing properties.

var convert = require('convert-source-map');

var json = convert
  .fromComment('//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoiYnVpbGQvZm9vLm1pbi5qcyIsInNvdXJjZXMiOlsic3JjL2Zvby5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiQUFBQSIsInNvdXJjZVJvb3QiOiIvIn0=')
  .toJSON();

var modified = convert
  .fromComment('//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoiYnVpbGQvZm9vLm1pbi5qcyIsInNvdXJjZXMiOlsic3JjL2Zvby5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiQUFBQSIsInNvdXJjZVJvb3QiOiIvIn0=')
  .setProperty('sources', [ 'SRC/FOO.JS' ])
  .toJSON();

console.log(json);
console.log(modified);

{"version":3,"file":"build/foo.min.js","sources":["src/foo.js"],"names":[],"mappings":"AAAA","sourceRoot":"/"}
{"version":3,"file":"build/foo.min.js","sources":["SRC/FOO.JS"],"names":[],"mappings":"AAAA","sourceRoot":"/"}

Upgrading#

Prior to v2.0.0, the fromMapFileComment and fromMapFileSource functions took a String directory path and used that to resolve & read the source map file from the filesystem. However, this made the library limited to nodejs environments and broke on sources with querystrings.

In v2.0.0, you now need to pass a function that does the file reading. It will receive the source filename as a String that you can resolve to a filesystem path, URL, or anything else.

If you are using convert-source-map in nodejs and want the previous behavior, you'll use a function like such:

+ var fs = require('fs'); // Import the fs module to read a file
+ var path = require('path'); // Import the path module to resolve a path against your directory
- var conv = convert.fromMapFileSource(css, '../my-dir');
+ var conv = convert.fromMapFileSource(css, function (filename) {
+   return fs.readFileSync(path.resolve('../my-dir', filename), 'utf-8');
+ });

API#

fromObject(obj)#

Returns source map converter from given object.

fromJSON(json)#

Returns source map converter from given json string.

fromURI(uri)#

Returns source map converter from given uri encoded json string.

fromBase64(base64)#

Returns source map converter from given base64 encoded json string.

fromComment(comment)#

Returns source map converter from given base64 or uri encoded json string prefixed with //# sourceMappingURL=....

fromMapFileComment(comment, readMap)#

Returns source map converter from given filename by parsing //# sourceMappingURL=filename.

readMap must be a function which receives the source map filename and returns either a String or Buffer of the source map (if read synchronously), or a Promise containing a String or Buffer of the source map (if read asynchronously).

If readMap doesn't return a Promise, fromMapFileComment will return a source map converter synchronously.

If readMap returns a Promise, fromMapFileComment will also return Promise. The Promise will be either resolved with the source map converter or rejected with an error.

Examples#

Synchronous read in Node.js:

var convert = require('convert-source-map');
var fs = require('fs');

function readMap(filename) {
  return fs.readFileSync(filename, 'utf8');
}

var json = convert
  .fromMapFileComment('//# sourceMappingURL=map-file-comment.css.map', readMap)
  .toJSON();
console.log(json);

Asynchronous read in Node.js:

var convert = require('convert-source-map');
var { promises: fs } = require('fs'); // Notice the `promises` import

function readMap(filename) {
  return fs.readFile(filename, 'utf8');
}

var converter = await convert.fromMapFileComment('//# sourceMappingURL=map-file-comment.css.map', readMap)
var json = converter.toJSON();
console.log(json);

Asynchronous read in the browser:

var convert = require('convert-source-map');

async function readMap(url) {
  const res = await fetch(url);
  return res.text();
}

const converter = await convert.fromMapFileComment('//# sourceMappingURL=map-file-comment.css.map', readMap)
var json = converter.toJSON();
console.log(json);

fromSource(source)#

Finds last sourcemap comment in file and returns source map converter or returns null if no source map comment was found.

fromMapFileSource(source, readMap)#

Finds last sourcemap comment in file and returns source map converter or returns null if no source map comment was found.

If readMap doesn't return a Promise, fromMapFileSource will return a source map converter synchronously.

If readMap returns a Promise, fromMapFileSource will also return Promise. The Promise will be either resolved with the source map converter or rejected with an error.

toObject()#

Returns a copy of the underlying source map.

toJSON([space])#

Converts source map to json string. If space is given (optional), this will be passed to JSON.stringify when the JSON string is generated.

toURI()#

Converts source map to uri encoded json string.

toBase64()#

Converts source map to base64 encoded json string.

toComment([options])#

Converts source map to an inline comment that can be appended to the source-file.

By default, the comment is formatted like: //# sourceMappingURL=..., which you would normally see in a JS source file.

When options.encoding == 'uri', the data will be uri encoded, otherwise they will be base64 encoded.

When options.multiline == true, the comment is formatted like: /*# sourceMappingURL=... */, which you would find in a CSS source file.

addProperty(key, value)#

Adds given property to the source map. Throws an error if property already exists.

setProperty(key, value)#

Sets given property to the source map. If property doesn't exist it is added, otherwise its value is updated.

getProperty(key)#

Gets given property of the source map.

removeComments(src)#

Returns src with all source map comments removed

removeMapFileComments(src)#

Returns src with all source map comments pointing to map files removed.

commentRegex#

Provides a fresh RegExp each time it is accessed. Can be used to find source map comments.

Breaks down a source map comment into groups: Groups: 1: media type, 2: MIME type, 3: charset, 4: encoding, 5: data.

mapFileCommentRegex#

Provides a fresh RegExp each time it is accessed. Can be used to find source map comments pointing to map files.

generateMapFileComment(file, [options])#

Returns a comment that links to an external source map via file.