8.7 KiB
Overview
Resolve the source map and/or sources for a generated file.
var sourceMapResolve = require("source-map-resolve")
var sourceMap = require("source-map")
var code = [
"!function(){...}();",
"/*# sourceMappingURL=foo.js.map */"
].join("\n")
sourceMapResolve.resolveSourceMap(code, "/js/foo.js", fs.readFile, function(error, result) {
if (error) {
return notifyFailure(error)
}
result
// {
// map: {file: "foo.js", mappings: "...", sources: ["/coffee/foo.coffee"], names: []},
// url: "/js/foo.js.map",
// sourcesRelativeTo: "/js/foo.js.map",
// sourceMappingURL: "foo.js.map"
// }
sourceMapResolve.resolveSources(result.map, result.sourcesRelativeTo, fs.readFile, function(error, result) {
if (error) {
return notifyFailure(error)
}
result
// {
// sourcesResolved: ["/coffee/foo.coffee"],
// sourcesContent: ["<contents of /coffee/foo.coffee>"]
// }
})
})
sourceMapResolve.resolve(code, "/js/foo.js", fs.readFile, function(error, result) {
if (error) {
return notifyFailure(error)
}
result
// {
// map: {file: "foo.js", mappings: "...", sources: ["/coffee/foo.coffee"], names: []},
// url: "/js/foo.js.map",
// sourcesRelativeTo: "/js/foo.js.map",
// sourceMappingURL: "foo.js.map",
// sourcesResolved: ["/coffee/foo.coffee"],
// sourcesContent: ["<contents of /coffee/foo.coffee>"]
// }
result.map.sourcesContent = result.sourcesContent
var map = new sourceMap.sourceMapConsumer(result.map)
map.sourceContentFor("/coffee/foo.coffee")
// "<contents of /coffee/foo.coffee>"
})
Installation
npm install source-map-resolve
bower install source-map-resolve
component install lydell/source-map-resolve
Works with CommonJS, AMD and browser globals, through UMD.
Note: This module requires setImmediate
and atob
.
Use polyfills if needed, such as:
Usage
sourceMapResolve.resolveSourceMap(code, codeUrl, read, callback)
code
is a string of code that may or may not contain a sourceMappingURL comment. Such a comment is used to resolve the source map.codeUrl
is the url to the file containingcode
. If the sourceMappingURL is relative, it is resolved againstcodeUrl
.read(url, callback)
is a function that readsurl
and responds usingcallback(error, content)
. In Node.js you might want to usefs.readFile
, while in the browser you might want to use an asynchronusXMLHttpRequest
.callback(error, result)
is a function that is invoked with either an error ornull
and the result.
The result is an object with the following properties:
map
: The source map forcode
, as an object (not a string).url
: The url to the source map. If the source map came from a data uri, this property isnull
, since then there is no url to it.sourcesRelativeTo
: The url that the sources of the source map are relative to. Since the sources are relative to the source map, and the url to the source map is provided as theurl
property, this property might seem superfluos. However, remember that theurl
property can benull
if the source map came from a data uri. If so, the sources are relative to the file containing the data uri—codeUrl
. This property will be identical to theurl
property orcodeUrl
, whichever is appropriate. This way you can conveniently resolve the sources without having to think about where the source map came from.sourceMappingURL
: The url of the sourceMappingURL comment incode
.
If code
contains no sourceMappingURL, the result is null
.
sourceMapResolve.resolveSources(map, mapUrl, read, [options], callback)
map
is a source map, as an object (not a string).mapUrl
is the url to the file containingmap
. Relative sources in the source map, if any, are resolved againstmapUrl
.read(url, callback)
is a function that readsurl
and responds usingcallback(error, content)
. In Node.js you might want to usefs.readFile
, while in the browser you might want to use an asynchronusXMLHttpRequest
.options
is an optional object with any of the following properties:sourceRoot
: Override thesourceRoot
property of the source map, which might only be relevant when resolving sources in the browser. This lets you bypass it when using the module outside of a browser, if needed. Pass a string to replace thesourceRoot
property with, orfalse
to ignore it. Defaults toundefined
.
callback(error, result)
is a function that is invoked with either an error ornull
and the result.
The result is an object with the following properties:
sourcesResolved
: The same asmap.sources
, except all the sources are fully resolved.sourcesContent
: An array with the contents of all sources inmap.sources
, in the same order asmap.sources
. If getting the contents of a source fails, an error object is put into the array instead.
sourceMapResolve.resolve(code, codeUrl, read, [options], callback)
The arguments are identical to sourceMapResolve.resolveSourceMap
, except that
you may also provide the same options
as in sourceMapResolve.resolveSources
.
This is a convenience method that first resolves the source map and then its
sources. You could also do this by first calling
sourceMapResolve.resolveSourceMap
and then sourceMapResolve.resolveSources
.
The result is identical to sourceMapResolve.resolveSourceMap
, with the
properties from sourceMapResolve.resolveSources
merged into it.
There is one extra feature available, though. If code
is null
, codeUrl
is
treated as a url to the source map instead of to code
, and will be read. This
is handy if you sometimes get the source map url from the SourceMap: <url>
header (see the Notes section). In this case, the sourceMappingURL
property
of the result is null
.
sourceMapResolve.*Sync()
There are also sync versions of the three previous functions. They are identical to the async versions, except:
- They expect a sync reading function. In Node.js you might want to use
fs.readFileSync
, while in the browser you might want to use a synchronusXMLHttpRequest
. - They throw errors and return the result instead of using a callback.
sourceMapResolve.resolveSourcesSync
also accepts null
as the read
parameter. The result is the same as when passing a function as the read parameter
, except that the sourcesContent
property of the result will be an
empty array. In other words, the sources aren’t read. You only get the
sourcesResolved
property. (This only supported in the synchronus version, since
there is no point doing it asynchronusly.)
sourceMapResolve.parseMapToJSON(string, [data])
The spec says that if a source map (as a string) starts with )]}'
, it should
be stripped off. This is to prevent XSSI attacks. This function does that and
returns the result of JSON.parse
ing what’s left.
If this function throws error
, error.sourceMapData === data
.
Errors
All errors passed to callbacks or thrown by this module have a sourceMapData
property that contain as much as possible of the intended result of the function
up until the error occurred.
Note that while the map
property of result objects always is an object,
error.sourceMapData.map
will be a string if parsing that string fails.
Note
This module resolves the source map for a given generated file by looking for a
sourceMappingURL comment. The spec defines yet a way to provide the URL to the
source map: By sending the SourceMap: <url>
header along with the generated
file. Since this module doesn’t retrive the generated code for you (instead
you give the generated code to the module), it’s up to you to look for such a
header when you retrieve the file (should the need arise).
Development
Tests
First off, run npm install
to install testing modules and browser polyfills.
npm test
lints the code and runs the test suite in Node.js.
x-package.json5
package.json, component.json and bower.json are all generated from
x-package.json5 by using xpkg
. Only edit x-package.json5, and remember to
run xpkg
before commiting!
Generating the browser version
source-map-resolve.js is generated from source-map-resolve-node.js and
source-map-resolve-template.js. Only edit the two latter files, not
source-map-resolve.js! To generate it, run npm run build
.