Gulpfile for using Less compiler with sourcemap support and autoprefixer postcss

gulpfile.js

var lessSourceFiles = '../../static/less/*.less'
var cssOutPath = '../../static/css'

var gulp = require('gulp')
var watch = require('gulp-watch')
var less = require('gulp-less-sourcemap')
var path = require('path')
var gutil = require('gulp-util')
var notifier = require('node-notifier')
var postcss      = require('gulp-postcss')
var sourcemaps   = require('gulp-sourcemaps')
var autoprefixer = require('autoprefixer-core')
var runSequence = require('run-sequence')
var fs = require('fs')

lessSourceFiles = path.resolve(lessSourceFiles)

gulp.task('less', function () {
    var cssDestination = cssOutPath

    return gulp
        .src(lessSourceFiles)
        .pipe(
        less({
                ieCompat: true,
                sourceMap: {
                    sourceMapRootpath: '../less'
                }
            })
        )
        .on('error', function (error) {
            gutil.log(gutil.colors.red(error.message))
            notifier.notify({title: 'Less compilation error', message: error.message})
            this.emit('end');
        })
        .pipe(gulp.dest(path.join(cssDestination)))
});

gulp.task('autoprefixer', function () {
    return gulp.src(path.join(cssOutPath, '*.css'))
        .pipe(sourcemaps.init())
        .pipe(
            postcss([
                autoprefixer({browsers: ['last 2 version', '> 1%', 'ie >= 8', 'Firefox > 15', 'iOS >= 5', 'Android >= 2.3']})
            ])
            .on('error', function (error) {
                notifier.notify({title: 'Autoprefixer compilation error', message: error.message.replace(/"+/, "'")})
                gutil.log(gutil.colors.red(error.message))
                this.emit('end');
            })
        )
        .pipe(sourcemaps.write('.'))
        .pipe(gulp.dest(cssOutPath))
})

gulp.task('begin-watching', function () {
    watch(path.join(path.dirname(lessSourceFiles), '**', '*.less'), function (file) {
        runSequence(
            'less',
            'autoprefixer'
        )
    })
})

gulp.task('watch', function (callback) {
    runSequence(
        'less',
        'autoprefixer',
        'begin-watching',
        callback
    )
})

gulp.task('default', ['watch']);