gulpfile.js

const path = require('path');
const chalk = require('chalk');
const gulp = require('gulp');
const prefixer = require('gulp-autoprefixer');
const concat = require('gulp-concat');
const plumber = require('gulp-plumber');
const sass = require('gulp-sass');
const sourcemaps = require('gulp-sourcemaps');

/**
 * ---------------------------------------------------------------------
 * Constants and utils.
 * ---------------------------------------------------------------------
 */

const SRC_PATHS = {
  sass: path.join(__dirname, 'resources/assets/sass/*.scss'),
  js: path.join(__dirname, 'resources/assets/js/**/*.js')
};

const WATCH_PATHS = {
  sass: [
    path.join(__dirname, 'resources/assets/sass/**/**/*.scss'),
    path.join(__dirname, 'resources/assets/sass/**/**/**/*.scss')
  ],
  js: path.join(__dirname, 'resources', 'assets', 'js', '**', '*.js')
};

const DEST_PATHS = {
  sass: path.join(__dirname, 'public/css'),
  js: path.join(__dirname, 'public/js')
};

const countTask = (() => {
  let taskNumber = 1;

  return (taskName, color = 'yellow') => {
    const title = chalk.bgWhite.black('[  TASK  ]');
    const task = chalk[color](`[${taskName}]`);
    const number = chalk.blue(`${taskNumber++}`.padStart(4, '0'));
    console.log(chalk.bold(`${title} ${task}: ${number}`));
  };
})();

/**
 * ---------------------------------------------------------------------
 * Tasks.
 * ---------------------------------------------------------------------
 */

function sassTask(done) {
  countTask('Sass', 'magenta');

  gulp
    .src(SRC_PATHS.sass)
    .pipe(plumber())
    .pipe(sourcemaps.init())
    .pipe(sass({ outputStyle: 'compressed' }))
    .pipe(prefixer())
    .pipe(sourcemaps.write('.'))
    .pipe(gulp.dest(DEST_PATHS.sass));

  done();
}

function jsTask(done) {
  countTask('JS', 'yellow');

  gulp
    .src(SRC_PATHS.js)
    .pipe(concat('index.js'))
    .pipe(gulp.dest(DEST_PATHS.js));

  done();
}

function watchTask(done) {
  gulp.watch(WATCH_PATHS.js, jsTask);
  gulp.watch(WATCH_PATHS.sass, sassTask);

  done();
}

exports.__js = jsTask;
exports.__sass = sassTask;
exports.__watch = watchTask;
exports.build = gulp.series(jsTask, sassTask);
exports.default = exports.dev = gulp.series(jsTask, sassTask, watchTask);