gulpfile.js

const gulp = require('gulp');
const imagemin = require('gulp-imagemin');
const uglify = require('gulp-uglify');
const sass = require('gulp-sass');
const concat = require('gulp-concat');


// logs message
gulp.task('message', function () {
    return console.log(`Gulp is running...`);
});

// copy all HTML files
gulp.task('copyHtml', () => {
    gulp.src('src/*.html')
        .pipe(gulp.dest('dist'));
});

// Optimize Images
gulp.task('imageMin', () => {
    gulp.src('src/images/*')
        .pipe(imagemin())
        .pipe(gulp.dest('dist/images'));
});


// Minify Js
gulp.task('minify', () => {
    gulp.src('src/js/*.js')
        .pipe(uglify())
        .pipe(gulp.dest('dist/js'));

});

// Compile Sass
gulp.task('sass', () => {
    gulp.src('src/sass/*.scss')
        .pipe(sass().on('error', sass.logError))
        .pipe(gulp.dest('dist/css'));
});

// Scripts   (Concat file)
gulp.task('scripts', () => {
    gulp.src('src/js/*.js')
        .pipe(concat('main.js'))
        .pipe(uglify())
        .pipe(gulp.dest('dist/js'));

});

gulp.task('default', gulp.series(gulp.parallel('message', 'copyHtml', 'imageMin', 'minify', 'sass', 'scripts')));

gulp.task('watch', () => {
    gulp.watch('src/js/*.js', gulp.series('scripts'));
    gulp.watch('src/images/*', gulp.series('imageMin'));
    gulp.watch('src/sass/*.scss', gulp.series('sass'));
    gulp.watch('src/*.html', gulp.series('copyHtml'));
});