gulpfile.js

var gulp         = require("gulp"),
    sass         = require("gulp-sass"),
    autoprefixer = require("gulp-autoprefixer"),
    hash         = require("gulp-hash"),
    del          = require("del"),
    runSequence  = require('run-sequence'),
    cp           = require('child_process'),
    rimraf       = require('rimraf');

// Compile SCSS files to CSS
gulp.task("scss", function () {
    //Delete our old css files
    del.sync(["static/css/**/*"]);
    //compile hashed css files
    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(hash())
        .pipe(gulp.dest("static/js"))
        .pipe(hash.manifest("hash.json"))
        .pipe(gulp.dest("data/images"));
});

// 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("build", () => {
    del.sync("public");
    runSequence(["scss", "images", "js"]);
});