Gulpfile w/ cache buster replacement

gulpfile.js

var gulp      = require('gulp');
var plumber   = require('gulp-plumber'); // used for error catching during watch
var sass      = require("gulp-sass");
var changed   = require('gulp-changed'); // only move changed files
var replace   = require("gulp-replace");
var concat    = require("gulp-concat");

var sourcePaths = {
  styles:    ['./scss/*.scss'],
  scripts:   ['./js/savings_slider.js', './js/jw_custom.js'],
  version:   './cache-version.php'
};

var distPaths = {
  styles:    './css',
  scripts:   './js'
};

gulp.task('styles', ['version'], function() {
  return gulp.src( sourcePaths.styles )
    .pipe(plumber())
    .pipe(changed(distPaths.styles))
    .pipe(sass({ errLogToConsole: true }))
    .pipe(gulp.dest( distPaths.styles ));
});

gulp.task('scripts', ['version'], function() {
  return gulp.src( sourcePaths.scripts )
    .pipe(plumber())
    .pipe(concat('scripts.js'))
    .pipe(gulp.dest( distPaths.scripts ));
});

gulp.task('version', function() {
  // Do an in-place replace
  var random = Math.floor((Math.random() * 9999) + 1);
  return gulp.src( sourcePaths.version )
    .pipe(replace(/'CACHE_BUSTER_VERSION', '(\d+)'/g, "'CACHE_BUSTER_VERSION', '"+ random +"'"))
    .pipe(gulp.dest('./'));
});

// Rerun the task when a file changes
gulp.task('watch', function(){
  gulp.watch(sourcePaths.styles, ['styles']);
  gulp.watch(sourcePaths.scripts, ['scripts']);
});

gulp.task('build', ['styles', 'scripts']);

// The default task (called when you run `gulp` from cli)
gulp.task('default', ['build', 'watch']);