Gulp web automation

gulpfile.js

const { src, dest, series, watch }  = require('gulp');
const del = require('del');
const sass = require('gulp-sass')(require('sass'));
const plumber = require("gulp-plumber");
const uglify = require("gulp-uglify");
const cssmin = require("gulp-cssmin");
const htmlmin = require("gulp-htmlmin");
const babel = require('gulp-babel');
const prefix = require('gulp-autoprefixer');
const mocha = require('gulp-mocha');
const browserSync = require('browser-sync').create();

//DEFAULT TASK
function defaultTask(cb) {
  // place code for your default task here
  cb();
}

//GULP SASS
function buildStylesTask(cb){
  return src('./sass/**/*.scss')
    .pipe(plumber())
    .pipe(sass().on('error', sass.logError))
    .pipe(prefix())
    .pipe(cssmin())
    .pipe(dest('./dist/css/'))
}


//CLEANUP
async function cleanup(){
  await del(['./dist/**']);
}

//BABEL - GIVE SUPPORT FOR ES2015 AND UGLIFY
function buildBabel(){
  return src('./js/**/!(*.spec).js')
    .pipe(plumber())
    .pipe(babel({
      presets: ['@babel/env']
  }))
    .pipe(uglify())
    .pipe(dest('./dist/js/'))
}

//MOCHA - GIVE MOCHA SUPPORT FOR TESTING
async function buildTest(){
  return await src('./test/**/*.spec.js')
        .pipe(plumber())
        .pipe(mocha())
        .once('error', err => {
          console.error('The tests failed to complete with below reason ',{error:err});
          process.exit(1);
        })
        .once('end', () => {
          process.exit();
        })
}


//BUILDING HTML
function buildHTML(){
  return src('./html/**/*.html')
    .pipe(htmlmin({
      collapseWhitespace:true,
      collapseInlineTagWhitespace:true,
      removeTagWhitespace:true
    }))
    .pipe(dest('./dist/'));
}

//WATCHING BUILD FILES
exports.watch = function buildWatch(){
  watch('./sass/**/*.scss',buildStylesTask).on("change",browserSync.reload);
  watch('./js/**/*.js',buildBabel).on("change",browserSync.reload);
  watch('./html/**/*.html',buildHTML).on("change",browserSync.reload);
  browserSync.init({
    server: "./dist/",
    port:8088,
    https:true,
    cors:true
});
}




exports.default = defaultTask;
exports.buildcss = buildStylesTask;
exports.buildjs = buildBabel;
exports.buildhtml = buildHTML;
exports.cleanup = cleanup;
exports.test = buildTest;
exports.build = series(cleanup,buildStylesTask,buildBabel,buildHTML);