gulpfile.js

var gulp = require("gulp");
var sass = require("gulp-sass");
var autoprefixer = require("gulp-autoprefixer");
var hash = require("gulp-hash");
var del = require("del");
var babel = require("gulp-babel");

// Compile SCSS files to CSS
gulp.task("scss", function () {
    del(["static/css/**/*"]);
    gulp.src("src/scss/**/*.scss")
        .pipe(sass({
            outputStyle: "compressed"
        }))
        .pipe(autoprefixer({
            browsers: ["last 20 versions"]
        }))
        .pipe(hash())
        .pipe(gulp.dest("static/css"))
        //Create a hash map
        .pipe(hash.manifest("hash.json"))
        //Put the map in the data directory
        .pipe(gulp.dest("data/css"));
});

// Hash images
gulp.task("images", function () {
    del(["static/images/**/*"]);
    gulp.src("src/images/**/*")
        .pipe(hash())
        .pipe(gulp.dest("static/images"))
        .pipe(hash.manifest("hash.json"))
        .pipe(gulp.dest("data/images"));
});

// Hash javascript
gulp.task("js", function () {
    del(["static/js/**/*"]);
    gulp.src("src/js/**/*")
        .pipe(babel({ignore: 'gulpfile.js'}))
        .pipe(hash())
        .pipe(gulp.dest("static/js"))
        .pipe(hash.manifest("hash.json"))
        .pipe(gulp.dest("data/js"));
});


// Watch asset folder for changes
gulp.task("watch", ["scss", "images", "js"], function () {
    gulp.watch("src/scss/**/*", ["scss"]);
    gulp.watch("src/images/**/*", ["images"]);
    gulp.watch("src/js/**/*", ["js"]);
});

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