Resolve a chain of sourcemaps back to the original source


321.4.73 years ago3 years agoMinified + gzip package size for @cush/sorcery in KB


sorcery v1.4.7

Fork of Rich-Harris/sorcery that caters toward build tools.

const sorcery = require('sorcery');

// Returns a v3 source map.
const sourceMap = sorcery([
  {content: minifiedCode, map: {...}},
  transpiledCode, // <= a string with an inline map
  sourceCode, // <= the original source code

// Provide hooks into your file cache.
const sourceMap = sorcery(sources, {
  // Return a string or null for file requests.
  readFile(file) {
    return cache[file].read();
  // Return a string, object, false, or null for sourcemap requests.
  getMap(file) {
    return cache[file].sourceMap;


  • sourceRoot: ?string a relative path prepended to each source path when consumed
  • generatedFile: ?string where the generated file lives relative to the new sourcemap
  • includeContent: ?boolean whether to embed source contents in the new sourcemap (default: true)
  • readFile(file) read the contents of a file (may be a source or sourcemap)
  • getMap(file) get a sourcemap from your file cache

When defined, the sourceRoot option is assumed to be relative to the sourcemap's directory. When the sourcemap is consumed, the sourceRoot prepended to every path in its sources array.

When defined, the generatedFile option is assumed to be relative to the sourcemap's directory. This option merely sets the file property of the returned SourceMap object. Its value should be identical to wherever you save the content in relation to the generated sourcemap.

The readFile function is required if any source is missing its content. This usually occurs when a sourcemap has no sourcesContent property. It must return either a string or null.

The getMap function must return either a JSON string, a sourcemap object, or null. If this option is undefined (or you return null), the generated file is parsed for a sourceMappingURL comment at the end. If you already know that a file has no sourcemap, you should return false to avoid extra work.


The portal function takes the same arguments as sorcery, but it returns a function instead of a SourceMap object.

The returned function traces a (line: number, column: number) pair to its original source. It returns an object (or null if the pair is untraceable) which has the following properties:

  • source: ?string the original filename
  • line: number the original line
  • column: number the original column
  • name: ?string the original identifier
const trace = sorcery.portal(chain, options);
trace(1 /* one-based line */, 0 /* zero-based column */); // {source, line, column, name} || null



If you find any bugs or have a feature request, please open an issue on github!

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