gulp-changed
v5.0.2
Published
Only pass through changed files
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gulp-changed
Only pass through changed files
No more wasting precious time on processing unchanged files.
By default it's only able to detect whether files in the stream changed. If you require something more advanced like knowing if imports/dependencies changed, create a custom comparator, or use another plugin.
Install
npm install --save-dev gulp-changed
Usage
import gulp from 'gulp';
import changed from 'gulp-changed';
import ngAnnotate from 'gulp-ng-annotate'; // Just as an example
const SOURCE = 'src/*.js';
const DESTINATION = 'dist';
exports.default = () => (
gulp.src(SOURCE)
.pipe(changed(DESTINATION))
// `ngAnnotate` will only get the files that
// changed since the last time it was run
.pipe(ngAnnotate())
.pipe(gulp.dest(DESTINATION))
);
API
changed(destination, options?)
destination
Type: string | Function
Destination directory. Same as you put into gulp.dest()
.
This is needed to be able to compare the current files with the destination files.
Can also be a function returning a destination directory path.
options
Type: object
cwd
Type: string
Default: process.cwd()
Working directory the folder is relative to.
extension
Type: string
Extension of the destination files.
Useful if it differs from the original, like in the example below:
export const jade = () => (
gulp.src('src/**/*.jade')
.pipe(changed('app', {extension: '.html'}))
.pipe(jade())
.pipe(gulp.dest('app'))
);
hasChanged
Type: Function
Default: compareLastModifiedTime
Function that determines whether the source file is different from the destination file.
Built-in comparators
Named imports:
compareLastModifiedTime
compareContents
Example
export const jade = () => (
gulp.src('src/**/*.jade')
.pipe(changed('app', {hasChanged: changed.compareContents}))
.pipe(jade())
.pipe(gulp.dest('app'))
);
You can also supply a custom comparator function which will receive the following arguments and should return Promise
.
stream
(transform object stream) - Should be used to queuesourceFile
if it passes some comparisonsourceFile
(Vinyl file object)destPath
(string) - Destination forsourceFile
as an absolute path
transformPath
Type: Function
Function to transform the path to the destination file. Should return the absolute path to the (renamed) destination file.
Useful if you rename your file later on, like in the below example:
export const marked = () => (
gulp.src('src/content/about.md')
.pipe(changed('dist', {transformPath: newPath => path.join(path.dirname(newPath), path.basename(newPath, '.md'), 'index.html')}))
.pipe(marked())
.pipe(rename(newPath => path.join(path.dirname(newPath), path.basename(newPath, '.md'), 'index.html'))))
.pipe(gulp.dest('dist'))
);
In-place change monitoring
If you're looking to process source files in-place without any build output (formatting, linting, etc), have a look at gulp-changed-in-place.