Basic gulpfile.js to work a basic HTML/JS/LESS/Images project under Gulp.JS/Express

gulpfile.js

var gulp = require('gulp');
var less = require('gulp-less');
var uglify = require('gulp-uglify');
var watch = require('gulp-watch');
var imagemin = require('gulp-imagemin');
 
var EXPRESS_PORT = 4000;
var EXPRESS_ROOT = __dirname;
var LIVERELOAD_PORT = 35729;
 
gulp.task('less', function() {
  gulp.src('css/*.less')
    .pipe(watch())
    .pipe(less())
    .pipe(gulp.dest('assets'))
});

gulp.task('compress', function() {
  gulp.src('js/*.js')
    .pipe(uglify({outSourceMaps: true}))
    .pipe(gulp.dest('assets'))
});

gulp.task('imagemin', function () {
    gulp.src('images/*.*')
        .pipe(imagemin())
        .pipe(gulp.dest('assets/images'));
});

function startExpress() {
  var express = require('express');
  var app = express();
  app.use(require('connect-livereload')());
  app.use(express.static(EXPRESS_ROOT));
  app.listen(EXPRESS_PORT);
}

var lr;
function startLivereload() {
  lr = require('tiny-lr')();
  lr.listen(LIVERELOAD_PORT);
}
function notifyLivereload(event) {
  gulp.src(event.path, {read: false})
      .pipe(require('gulp-livereload')(lr));
}
 
gulp.task('default', function () {
 
  startExpress();
  startLivereload();

  gulp.watch('*.html', notifyLivereload);
  gulp.watch('js/*.js', function() {
    gulp.run('compress');
    notifyLivereload;
  });
  gulp.watch('css/*.less', function() {
    gulp.run('less');
    notifyLivereload;
  });
  gulp.watch('images/*.*', function() {
    gulp.run('imagemin');
    notifyLivereload;
  });
});