207 lines
		
	
	
		
			7.2 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			207 lines
		
	
	
		
			7.2 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
# convert-source-map [![Build Status][ci-image]][ci-url]
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Converts a source-map from/to  different formats and allows adding/changing properties.
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```js
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var convert = require('convert-source-map');
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var json = convert
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  .fromComment('//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoiYnVpbGQvZm9vLm1pbi5qcyIsInNvdXJjZXMiOlsic3JjL2Zvby5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiQUFBQSIsInNvdXJjZVJvb3QiOiIvIn0=')
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  .toJSON();
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var modified = convert
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  .fromComment('//# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoiYnVpbGQvZm9vLm1pbi5qcyIsInNvdXJjZXMiOlsic3JjL2Zvby5qcyJdLCJuYW1lcyI6W10sIm1hcHBpbmdzIjoiQUFBQSIsInNvdXJjZVJvb3QiOiIvIn0=')
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  .setProperty('sources', [ 'SRC/FOO.JS' ])
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  .toJSON();
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console.log(json);
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console.log(modified);
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```
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```json
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{"version":3,"file":"build/foo.min.js","sources":["src/foo.js"],"names":[],"mappings":"AAAA","sourceRoot":"/"}
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{"version":3,"file":"build/foo.min.js","sources":["SRC/FOO.JS"],"names":[],"mappings":"AAAA","sourceRoot":"/"}
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```
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## Upgrading
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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.
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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.
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If you are using `convert-source-map` in nodejs and want the previous behavior, you'll use a function like such:
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```diff
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+ var fs = require('fs'); // Import the fs module to read a file
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+ var path = require('path'); // Import the path module to resolve a path against your directory
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- var conv = convert.fromMapFileSource(css, '../my-dir');
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+ var conv = convert.fromMapFileSource(css, function (filename) {
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+   return fs.readFileSync(path.resolve('../my-dir', filename), 'utf-8');
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+ });
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```
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## API
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### fromObject(obj)
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Returns source map converter from given object.
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### fromJSON(json)
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Returns source map converter from given json string.
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### fromURI(uri)
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Returns source map converter from given uri encoded json string.
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### fromBase64(base64)
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Returns source map converter from given base64 encoded json string.
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### fromComment(comment)
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Returns source map converter from given base64 or uri encoded json string prefixed with `//# sourceMappingURL=...`.
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### fromMapFileComment(comment, readMap)
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Returns source map converter from given `filename` by parsing `//# sourceMappingURL=filename`.
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`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).
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If `readMap` doesn't return a `Promise`, `fromMapFileComment` will return a source map converter synchronously.
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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.
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#### Examples
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**Synchronous read in Node.js:**
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```js
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var convert = require('convert-source-map');
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var fs = require('fs');
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function readMap(filename) {
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  return fs.readFileSync(filename, 'utf8');
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}
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var json = convert
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  .fromMapFileComment('//# sourceMappingURL=map-file-comment.css.map', readMap)
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  .toJSON();
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console.log(json);
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```
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**Asynchronous read in Node.js:**
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```js
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var convert = require('convert-source-map');
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var { promises: fs } = require('fs'); // Notice the `promises` import
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function readMap(filename) {
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  return fs.readFile(filename, 'utf8');
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}
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var converter = await convert.fromMapFileComment('//# sourceMappingURL=map-file-comment.css.map', readMap)
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var json = converter.toJSON();
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console.log(json);
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```
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**Asynchronous read in the browser:**
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```js
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var convert = require('convert-source-map');
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async function readMap(url) {
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  const res = await fetch(url);
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  return res.text();
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}
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const converter = await convert.fromMapFileComment('//# sourceMappingURL=map-file-comment.css.map', readMap)
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var json = converter.toJSON();
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console.log(json);
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```
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### fromSource(source)
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Finds last sourcemap comment in file and returns source map converter or returns `null` if no source map comment was found.
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### fromMapFileSource(source, readMap)
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Finds last sourcemap comment in file and returns source map converter or returns `null` if no source map comment was found.
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`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).
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If `readMap` doesn't return a `Promise`, `fromMapFileSource` will return a source map converter synchronously.
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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.
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### toObject()
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Returns a copy of the underlying source map.
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### toJSON([space])
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Converts source map to json string. If `space` is given (optional), this will be passed to
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[JSON.stringify](https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/JSON/stringify) when the
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JSON string is generated.
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### toURI()
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Converts source map to uri encoded json string.
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### toBase64()
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Converts source map to base64 encoded json string.
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### toComment([options])
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Converts source map to an inline comment that can be appended to the source-file.
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By default, the comment is formatted like: `//# sourceMappingURL=...`, which you would
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normally see in a JS source file.
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When `options.encoding == 'uri'`, the data will be uri encoded, otherwise they will be base64 encoded.
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When `options.multiline == true`, the comment is formatted like: `/*# sourceMappingURL=... */`, which you would find in a CSS source file.
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### addProperty(key, value)
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Adds given property to the source map. Throws an error if property already exists.
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### setProperty(key, value)
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Sets given property to the source map. If property doesn't exist it is added, otherwise its value is updated.
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### getProperty(key)
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Gets given property of the source map.
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### removeComments(src)
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Returns `src` with all source map comments removed
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### removeMapFileComments(src)
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Returns `src` with all source map comments pointing to map files removed.
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### commentRegex
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Provides __a fresh__ RegExp each time it is accessed. Can be used to find source map comments.
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Breaks down a source map comment into groups: Groups: 1: media type, 2: MIME type, 3: charset, 4: encoding, 5: data.
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### mapFileCommentRegex
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Provides __a fresh__ RegExp each time it is accessed. Can be used to find source map comments pointing to map files.
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### generateMapFileComment(file, [options])
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Returns a comment that links to an external source map via `file`.
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By default, the comment is formatted like: `//# sourceMappingURL=...`, which you would normally see in a JS source file.
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When `options.multiline == true`, the comment is formatted like: `/*# sourceMappingURL=... */`, which you would find in a CSS source file.
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[ci-url]: https://github.com/thlorenz/convert-source-map/actions?query=workflow:ci
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[ci-image]: https://img.shields.io/github/workflow/status/thlorenz/convert-source-map/CI?style=flat-square
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