gulp-folder-changed

Gulp plugin to pass through files if they've changed

Install

npm install --save-dev gulp-folder-changed

Usage

Pass this into something like gulp-ignore to pass through all files in a folder if any of those files has changed.

To match against a single file, pass in the file path:

dest/
  styles.css
src/
  a.css
  b.css

var ignore = require('gulp-ignore'),
  folderChanged = require('gulp-folder-changed');

gulp.src('src/*.css')
  .pipe(ignore.include(folderChanged('dest/styles.css')))
  .pipe(doSomethingWithTheChangedFiles);

If you want to match against more than one file, use a glob:

dest/
  styles-1.css
  styles-2.css
src/
  a.css
  b.css

var ignore = require('gulp-ignore'),
  folderChanged = require('gulp-folder-changed');

gulp.src('src/*.css')
  .pipe(ignore.include(folderChanged('dest/styles-*.css')))
  .pipe(doSomethingWithTheChangedFiles);

You can also match against files with the same name as the source files:

dest/
  a.css
  b.css
src/
  a.css
  b.css

gulp.src('src/*.css')
  .pipe(ignore.include(folderChanged('dest/:name.css')))
  .pipe(doSomethingWithTheChangedFiles);

If you sort your source files into specific folders, you can match on the parent folder instead:

dest/
  folder1.css
  folder2.css
src/
  folder1/
    a.css
    b.css
  folder2/
    a.css
    b.css

gulp.src('src/**/*.css')
  .pipe(ignore.include(folderChanged('dest/:dirname.css')))
  .pipe(doSomethingWithTheChangedFiles);

You can also specify matching extensions (note: :ext includes the dot):

dest/
  foo.css
  foo.js
src/
  bar.css
  baz.js

gulp.src('src/**/*.css')
  .pipe(ignore.include(folderChanged('dest/foo:ext')))
  .pipe(doSomethingWithTheChangedFiles);

Combine them to create powerful matching schemas!

dest/
  foo-a.css
  foo-b.css
  foo-c.js
  bar-a.css
  bar-b.js
src/
  foo/
    a.css
    b.css
    c.js
  bar/
    a.css
    b.js

gulp.src('src/**/*.css')
  .pipe(ignore.include(folderChanged('dest/:dirname-:name:ext')))
  .pipe(doSomethingWithTheChangedFiles);

If you want to do something super custom, you can pass an object with either a parentName or parentDir (or both!) as a second argument:

dest/
  foo.css
  bar.css
src/
  foo/
    styles/
      a.css
      b.css
  bar/
    styles/
      a.css
      b.css

var path = require('path'),
  _ = require('lodash');

// src/foo/styles/a.css -> foo
function getName(filePath) {
  return _.last(_.dropRight(path.dirname(filePath).split(path.sep)));
}

// foo -> src/foo/styles
function getFolder(parentName) {
  return path.join('src', parentName, 'styles');
}

gulp.src('src/**/*.css')
  .pipe(ignore.include(folderChanged('dest/:dirname:ext', {
    parentName: getName,
    parentDir: getFolder
  })))
  .pipe(doSomethingWithTheChangedFiles);

Have fun!