Sourcemap support for gulpjs.
All the examples here works with Gulp 4. To see examples related to Gulp 3, you can read them here.
Inline source maps are embedded in the source file.
Example:
var gulp = require('gulp');
var plugin1 = require('gulp-plugin1');
var plugin2 = require('gulp-plugin2');
var sourcemaps = require('gulp-sourcemaps');
function javascript() {
gulp.src('src/**/*.js')
.pipe(sourcemaps.init())
.pipe(plugin1())
.pipe(plugin2())
.pipe(sourcemaps.write())
.pipe(gulp.dest('dist'));
};
exports.javascript = javascript;All plugins between sourcemaps.init() and sourcemaps.write() need to have support for gulp-sourcemaps. You can find a list of such plugins in the wiki.
To write external source map files, pass a path relative to the destination to sourcemaps.write().
Example:
var gulp = require('gulp');
var plugin1 = require('gulp-plugin1');
var plugin2 = require('gulp-plugin2');
var sourcemaps = require('gulp-sourcemaps');
function javascript() {
gulp.src('src/**/*.js')
.pipe(sourcemaps.init())
.pipe(plugin1())
.pipe(plugin2())
.pipe(sourcemaps.write('../maps'))
.pipe(gulp.dest('dist'));
};
exports.javascript = javascript;To load existing source maps, pass the option loadMaps: true to sourcemaps.init().
Example:
var gulp = require('gulp');
var plugin1 = require('gulp-plugin1');
var plugin2 = require('gulp-plugin2');
var sourcemaps = require('gulp-sourcemaps');
function javascript() {
gulp.src('src/**/*.js')
.pipe(sourcemaps.init({loadMaps: true}))
.pipe(plugin1())
.pipe(plugin2())
.pipe(sourcemaps.write())
.pipe(gulp.dest('dist'));
};
exports.javascript = javascript;To handle large files, pass the option largeFile: true to sourcemaps.init().
Example:
var gulp = require('gulp');
var plugin1 = require('gulp-plugin1');
var plugin2 = require('gulp-plugin2');
var sourcemaps = require('gulp-sourcemaps');
function javascript() {
gulp.src('src/**/*.js')
.pipe(sourcemaps.init({largeFile: true}))
.pipe(plugin1())
.pipe(plugin2())
.pipe(sourcemaps.write())
.pipe(gulp.dest('dist'));
};
exports.javascript = javascript;Use the base option on gulp.src to make sure all files are relative to a common base directory.
Example:
var gulp = require('gulp');
var plugin1 = require('gulp-plugin1');
var plugin2 = require('gulp-plugin2');
var sourcemaps = require('gulp-sourcemaps');
function javascript() {
gulp.src(['src/test.js', 'src/testdir/test2.js'], { base: 'src' })
.pipe(sourcemaps.init())
.pipe(plugin1())
.pipe(plugin2())
.pipe(sourcemaps.write('../maps'))
.pipe(gulp.dest('dist'));
};
exports.javascript = javascript;The exported mapSources method gives full control over the source paths. It takes a function that is called for every source and receives the default source path as a parameter and the original vinyl file.
Example:
function javascript() {
var stream = gulp.src('src/**/*.js')
.pipe(sourcemaps.init())
.pipe(plugin1())
.pipe(plugin2())
// be careful with the sources returned otherwise contents might not be loaded properly
.pipe(sourcemaps.mapSources(function(sourcePath, file) {
// source paths are prefixed with '../src/'
return '../src/' + sourcePath;
}))
.pipe(sourcemaps.write('../maps')
.pipe(gulp.dest('public/scripts'));
};
exports.javascript = javascript;The exported identityMap method allows you to generate a full valid source map encoding no changes (slower, only for Javascript and CSS) instead of the default empty source map (no mappings, fast). Use this option if you get missing or incorrect mappings, e.g. when debugging.
Example:
function javascript() {
var stream = gulp.src('src/**/*.js')
.pipe(sourcemaps.init())
// An identity sourcemap will be generated at this step
.pipe(sourcemaps.identityMap())
.pipe(plugin1())
.pipe(plugin2())
.pipe(sourcemaps.write('../maps')
.pipe(gulp.dest('public/scripts'));
};
exports.javascript = javascript;-
loadMapsSet to true to load existing maps for source files. Supports the following:
- inline source maps
- source map files referenced by a
sourceMappingURL=comment - source map files with the same name (plus .map) in the same directory
-
identityMapThis option is deprecated. Upgrade to use our
sourcemap.identityMapAPI.
-
addCommentBy default a comment containing / referencing the source map is added. Set this to
falseto disable the comment (e.g. if you want to load the source maps by header).Example:
function javascript() { var stream = gulp.src('src/**/*.js') .pipe(sourcemaps.init()) .pipe(plugin1()) .pipe(plugin2()) .pipe(sourcemaps.write('../maps', {addComment: false})) .pipe(gulp.dest('dist')); }; exports.javascript = javascript;
-
includeContentBy default the source maps include the source code. Pass
falseto use the original files.Including the content is the recommended way, because it "just works". When setting this to
falseyou have to host the source files and set the correctsourceRoot. -
sourceRootSet the location where the source files are hosted (use this when
includeContentis set tofalse). This is usually a URL (or an absolute URL path), not a local file system path. By default the source root is '' or in casedestPathis set, the relative path from the source map to the source base directory (this should work for many dev environments). If a relative path is used (empty string or one starting with a.), it is interpreted as a path relative to the destination. The plugin rewrites it to a path relative to each source map.Example:
function javascript() { var stream = gulp.src('src/**/*.js') .pipe(sourcemaps.init()) .pipe(plugin1()) .pipe(plugin2()) .pipe(sourcemaps.write({includeContent: false, sourceRoot: '/src'})) .pipe(gulp.dest('dist')); }; exports.javascript = javascript;
Example (using a function):
function javascript() { var stream = gulp.src('src/**/*.js') .pipe(sourcemaps.init()) .pipe(plugin1()) .pipe(plugin2()) .pipe(sourcemaps.write({ includeContent: false, sourceRoot: function(file) { return '/src'; } })) .pipe(gulp.dest('dist')); }; exports.javascript = javascript;
Example (relative path):
function javascript() { var stream = gulp.src('src/**/*.js') .pipe(sourcemaps.init()) .pipe(plugin1()) .pipe(plugin2()) .pipe(sourcemaps.write('.', {includeContent: false, sourceRoot: '../src'})) .pipe(gulp.dest('dist')); }; exports.javascript = javascript;
In this case for a file written to
dist/subdir/example.js, the source map is written todist/subdir/example.js.mapand the sourceRoot will be../../src(resulting in the full source path../../src/subdir/example.js). -
destPathSet the destination path (the same you pass to
gulp.dest()). If the source map destination path is not a sub path of the destination path, this is needed to get the correct path in thefileproperty of the source map. In addition, it allows to automatically set a relativesourceRootif none is set explicitly. -
sourceMappingURLPrefixSpecify a prefix to be prepended onto the source map URL when writing external source maps. Relative paths will have their leading dots stripped.
Example:
function javascript() { var stream = gulp.src('src/**/*.js') .pipe(sourcemaps.init()) .pipe(plugin1()) .pipe(plugin2()) .pipe(sourcemaps.write('../maps', { sourceMappingURLPrefix: 'https://asset-host.example.com/assets' })) .pipe(gulp.dest('public/scripts')); }; exports.javascript = javascript;
This will result in a source mapping URL comment like
sourceMappingURL=https://asset-host.example.com/assets/maps/helloworld.js.map. -
sourceMappingURLIf you need full control over the source map URL you can pass a function to this option. The output of the function must be the full URL to the source map (in function of the output file).
Example:
function javascript() { var stream = gulp.src('src/**/*.js') .pipe(sourcemaps.init()) .pipe(plugin1()) .pipe(plugin2()) .pipe(sourcemaps.write('../maps', { sourceMappingURL: function(file) { return 'https://asset-host.example.com/' + file.relative + '.map'; } })) .pipe(gulp.dest('public/scripts')); }; exports.javascript = javascript;
This will result in a source mapping URL comment like
sourceMappingURL=https://asset-host.example.com/helloworld.js.map. -
mapFileThis option allows to rename the map file. It takes a function that is called for every map and receives the default map path as a parameter.
Example:
function javascript() { var stream = gulp.src('src/**/*.js') .pipe(sourcemaps.init()) .pipe(plugin1()) .pipe(plugin2()) .pipe(sourcemaps.write('../maps', { mapFile: function(mapFilePath) { // source map files are named *.map instead of *.js.map return mapFilePath.replace('.js.map', '.map'); } })) .pipe(gulp.dest('public/scripts')); }; exports.javascript = javascript;
-
mapSourcesThis option is deprecated. Upgrade to use our
sourcemap.mapSourcesAPI. -
charsetSets the charset for inline source maps. Default:
utf8 -
cloneClones the original file for creation of the map file. Could be important if file history is important. See file.clone() for possible options. Default:
{deep:false, contents:false}
-
How to add source map support to plugins
- Generate a source map for the transformation the plugin is applying
- Important: Make sure the paths in the generated source map (
fileandsources) are relative tofile.base(e.g. usefile.relative). - Apply this source map to the vinyl
file. E.g. by using vinyl-sourcemaps-apply. This combines the source map of this plugin with the source maps coming from plugins further up the chain. - Add your plugin to the wiki page
var through = require('through2'); var applySourceMap = require('vinyl-sourcemaps-apply'); var myTransform = require('myTransform'); module.exports = function(options) { function transform(file, encoding, callback) { // generate source maps if plugin source-map present if (file.sourceMap) { options.makeSourceMaps = true; } // do normal plugin logic var result = myTransform(file.contents, options); file.contents = new Buffer(result.code); // apply source map to the chain if (file.sourceMap) { applySourceMap(file, result.map); } this.push(file); callback(); } return through.obj(transform); };
-
Verify sourcemaps are working
See example below or refer to test/write.js
var stream = plugin(); var init = sourcemaps.init(); var write = sourcemaps.write(); init.pipe(stream).pipe(write); write.on('data', function (file) { assert(...); cb(); }); init.write(new gutil.File(...)); init.end();
All debugging output relies on visionmedia/debug. Follow the directions to set the
environment variable $DEBUG.
For a few examples of debug you could use:
DEBUG='gulp-sourcemaps:*' #everything
DEBUG='gulp-sourcemaps:init' #init/index.js
DEBUG='gulp-sourcemaps:init:*' #init/index.internals.js
DEBUG='gulp-sourcemaps:write:' #write/index.js
DEBUG='gulp-sourcemaps:write:*' #write/index.internals.js
DEBUG='gulp-sourcemaps:write:,gulp-sourcemaps:init:**' #write/index.internals.js and init/index.internals.js
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