gulp-less

Less for Gulp

gulp-less

A LESS plugin for Gulp

npm install gulp-less
var less = require('gulp-less');
var path = require('path');
 
gulp.task('less', function () {
  return gulp.src('./less/**/*.less')
    .pipe(less({
      paths: [ path.join(__dirname, 'less', 'includes') ]
    }))
    .pipe(gulp.dest('./public/css'));
});

The options you can use can be found here. Below is a list of valid options as of the time of writing:

  • paths: Array of paths to be used for @import directives
  • plugins: Array of less plugins (details)

The filename option is not necessary, it's handled automatically by this plugin. The compress option is not supported -- if you are trying to minify your css, use gulp-minify-css. No sourceMap options are supported -- if you are trying to generate sourcemaps, use gulp-sourcemaps.

If you want to minify/compress your css, you can use either the gulp-minify-css plugin for gulp, or the less-clean-css plugin for less. Examples of both are shown below:

// Using a less plugin to minify css 
var LessPluginCleanCSS = require('less-plugin-clean-css'),
    cleancss = new LessPluginCleanCSS({ advanced: true });
 
gulp.src('./less/**/*.less')
  .pipe(less({
    plugins: [cleancss]
  }))
  .pipe(gulp.dest('./public/css'));
// Using a gulp plugin to minify css 
var minifyCSS = require('gulp-minify-css');
 
gulp.src('./less/**/*.less')
  .pipe(less())
  .pipe(minifyCSS())
  .pipe(gulp.dest('./public/css'));

Less now supports plugins, which can add additional functionality like minifying css as shown above. Here's an example of how to use plugins with gulp-less using both the clean-css plugin and the autoprefix plugin.

var LessPluginCleanCSS = require('less-plugin-clean-css'),
    LessPluginAutoPrefix = require('less-plugin-autoprefix'),
    cleancss = new LessPluginCleanCSS({ advanced: true }),
    autoprefix= new LessPluginAutoPrefix({ browsers: ["last 2 versions"] });
 
gulp.src('./less/**/*.less')
  .pipe(less({
    plugins: [autoprefix, cleancss]
  }))
  .pipe(gulp.dest('./public/css'));

More info on LESS plugins can be found at http://lesscss.org/usage/#plugins, including a current list of all available plugins.

gulp-less can be used in tandem with gulp-sourcemaps to generate source maps for your files. You will need to initialize gulp-sourcemaps prior to running the gulp-less compiler and write the source maps after, as such:

var sourcemaps = require('gulp-sourcemaps');
 
gulp.src('./less/**/*.less')
  .pipe(sourcemaps.init())
  .pipe(less())
  .pipe(sourcemaps.write())
  .pipe(gulp.dest('./public/css'));

By default, gulp-sourcemaps writes the source maps inline in the compiled CSS files. To write them to a separate file, specify a relative file path in the sourcemaps.write() function, as such:

var sourcemaps = require('gulp-sourcemaps');
 
gulp.src('./less/**/*.less')
  .pipe(sourcemaps.init())
  .pipe(less())
  .pipe(sourcemaps.write('./maps'))
  .pipe(gulp.dest('./public/css'));

By default, a gulp task will fail and all streams will halt when an error happens. To change this behavior check out the error handling documentation here

(MIT License)

Copyright (c) 2015 Plus 3 Network dev@plus3network.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.