gulpfile.js

var gulp = require("gulp");
var plumber = require("gulp-plumber");
var concat = require("gulp-concat");
var uglify = require("gulp-uglify");
var sass = require("gulp-sass");
var autoprefixer = require("gulp-autoprefixer");
var cssimport = require("gulp-cssimport");
var cssmin = require("gulp-cssmin");

gulp.task("script", function() {
  gulp.src([
    "node_modules/jquery/dist/jquery.min.js",
    "src/scripts/**/*.js"
  ])
    .pipe(plumber())
    .pipe(concat("script.js"))
    .pipe(uglify({
      output: {
        comments: /^!/
      }
    }))
    .pipe(gulp.dest("./assets/scripts"))
});

gulp.task("style", function() {
  gulp.src("src/styles/**/*.scss")
    .pipe(plumber())
    .pipe(sass())
    .pipe(autoprefixer())
    .pipe(cssimport({
      includePaths: ["styles"],
      skipComments: false,
    }))
    .pipe(cssmin())
    .pipe(gulp.dest("./assets/styles"))
});

gulp.task("image", function() {
  gulp.src("src/images/**/*.png")
    .pipe(gulp.dest("./assets/images"))
});

gulp.task("build", ["script", "style", "image"]);

gulp.task("default", function() {
  gulp.watch("src/scripts/**/*.js", ["script"]);
  gulp.watch("src/styles/**/*.scss", ["style"]);
  gulp.watch("src/images/**/*.png", ["image"]);
});