gulpfile.js

// Gulpfile
"use strict";
const gulp = require('gulp');
const sass = require('gulp-sass');
const autoprefixer = require('gulp-autoprefixer');
const rename = require('gulp-rename');
const concat = require('gulp-concat');
const cleanCSS = require('gulp-clean-css');
const uglify = require('gulp-uglify-es').default;
const browsersync = require('browser-sync').create();

// Gulp plumber error handler - displays if any error occurs during the process on your command
function errorLog(error) {
  console.error.bind(error);
  this.emit('end');
}

// SASS - Compile SASS files into CSS
function scss() {
  return gulp
    .src('./assets/scss/**/*.scss')
    .pipe(sass({outputStyle: 'expanded'}))
    .pipe(cleanCSS({compatibility: 'ie11'}))
    .pipe(rename({suffix: '.min'}))
    .pipe(gulp.dest('./assets/css/'))
    .on('error', sass.logError)
    .pipe(autoprefixer([
      "last 1 major version",
      ">= 1%",
      "Chrome >= 45",
      "Firefox >= 38",
      "Edge >= 12",
      "Explorer >= 10",
      "iOS >= 9",
      "Safari >= 9",
      "Android >= 4.4",
      "Opera >= 30"], {cascade: true}))
    .pipe(gulp.dest('./assets/css/'))
    .pipe(browsersync.stream());
}

// BrowserSync (live reload) - keeps multiple browsers & devices in sync when building websites
function browserSync(done) {
  browsersync.init({
    files: "./*.html",
    startPath: "./index.html",
    server: {
      baseDir: "./",
      routes: {},
      middleware: function (req, res, next) {
        if (/\.json|\.txt|\.html/.test(req.url) && req.method.toUpperCase() == 'POST') {
          console.log('[POST => GET] : ' + req.url);
          req.method = 'GET';
        }
        next();
      }
    }
  });
  done();
}

function browserSyncReload(done) {
  browsersync.reload();
  done();
}

// Gulp Watch and Tasks
function watch() {
  gulp.watch('./assets/scss/**/*.scss', scss);
  gulp.watch(
    [
      './*.html',
      './html/**/*.html'
    ],
    gulp.series(browserSyncReload)
  );
}

// JavaSript minifier - merges and minifies the below given list of Space libraries into one theme.min.js
function minJS() {
  return gulp
    .src([
      './assets/js/theme-custom.js',
    ])
    .pipe(concat('theme.min.js'))
    .pipe(uglify())
    .pipe(gulp.dest('./assets/js/dist/'));
}

// Copy Vendors - a utility to copy client-side dependencies into a folder
function copyVendors() {
  return gulp
    .src([
      './node_modules/*bootstrap/**/*',
      './node_modules/*aos/**/*',
    ])
    .pipe(gulp.dest('./assets/vendor/'))
}

// Gulp Tasks
gulp.task('default', gulp.parallel(watch, scss, browserSync));
gulp.task('minJS', minJS);
gulp.task('copyVendors', copyVendors);
gulp.task('dist', gulp.series(copyVendors, minJS));