A gulp file for my dist build

gulpfile.js

var htmlmin = require('gulp-htmlmin');
var cleanCSS = require('gulp-clean-css');
var minify = require('gulp-minify');
const gulp = require('gulp'),
    del = require('del'),
    runSequence = require('run-sequence'),
    src = `${__dirname}/.`,
    dist = `${__dirname}/public`;
    workbox = require('workbox-build');
    imagemin = require('gulp-imagemin');
    var minify = require('gulp-minifier');

gulp.task('clean', () => {
  return del(dist);
});

gulp.task('build', () => {
  gulp.src(`${src}/**/*`)
      .pipe(gulp.dest(dist));
});

gulp.task('generate-service-worker', () => {
  return workbox.generateSW({
    globDirectory: dist,
    globPatterns: ['**\/*.{html,js}'],
    swDest: `${dist}/sw.js`,
    clientsClaim: true,
    skipWaiting: true,
    runtimeCaching: [
      {
        urlPattern: new RegExp('http://139.59.3.54:8000/'),
        handler: 'staleWhileRevalidate'
      }
    ],
  }).then(() => {
  }).catch((error) => {
  });

});



gulp.task('minify_img', () =>
    gulp.src('images/*\*')
        .pipe(imagemin([],{
          verbose: true
        }))
        .pipe(imagemin({
          interlaced: true,
          progressive: true,
          optimizationLevel: 10,
          svgoPlugins: [{removeViewBox: true}]
      }))
        .pipe(gulp.dest('public/images'))
        
);
 
gulp.task('minify_all', function() {
  return gulp.src('./css/*').pipe(minify({
    minify: true,
    collapseWhitespace: true,
    conservativeCollapse: true,
    minifyJS: true,
    minifyCSS: true,
    getKeptComment: function (content, filePath) {
        var m = content.match(/\/\*![\s\S]*?\*\//img);
        return m && m.join('\n') + '\n' || '';
    }
  })).pipe(gulp.dest('public/'));
});

gulp.task('default', () => {
  runSequence(['build','generate-service-worker','minify_html','minify-css','minify_js']);
});

gulp.task('minify_html', function() {
  return gulp.src('*.html')
    .pipe(htmlmin({collapseWhitespace: true}))
    .pipe(gulp.dest('public'));
});

gulp.task('minify-css', () => {
  return gulp.src('css/*.css')
    .pipe(cleanCSS({compatibility: 'ie8'},{debug: true}, (details) => {
    }))
    .pipe(gulp.dest('public/css/'));
});


gulp.task('minify_js', function() {
  gulp.src('js/*.js')
    .pipe(minify({
        ext:{
            src:'-debug.js',
            min:'.js'
        },
        exclude: ['tasks'],
        ignoreFiles: ['.combo.js', '-min.js']
    }))
    .pipe(gulp.dest('public/js'))
});