gulpfile.js

// Use npm install to install all the dependencies located in package.json
const gulp = require('gulp');
const concat = require('gulp-concat');
const uglify = require('gulp-uglify');
const imagemin = require('gulp-imagemin');
const gutil = require('gulp-util');
const shell = require('gulp-shell');
const less = require('gulp-less');
const cssmin = require('gulp-cssmin')
const replace = require('gulp-replace');

gulp.task('js', function () {
    gutil.log('... Minifying js');
    gulp.src(['assets/js/partials/**.js'])
        .pipe(concat('main.min.js'))
        .pipe(uglify())
        .on('error', (err) => {
            gutil.log(gutil.colors.red('[Error]'), err.toString());
        })
        .pipe(gulp.dest("assets/js/"))
});

gulp.task("img", function () {
    gutil.log('... Minifying images');
    gulp.src('assets/img/**/*.{png,svg,jpg,gif}')
        .pipe(imagemin())
        .on('error', (err) => {
            gutil.log(gutil.colors.red('[Error]'), err.toString());
        })
        .pipe(gulp.dest('assets/img/'))
});

gulp.task('minify-bootstrap-css', function () {
    gutil.log('... Minifying isolated bootstrap');
    gulp.src('assets/css/vendor/bootstrap-iso.css')
        .pipe(cssmin())
        .on('error', (err) => {
            gutil.log(gutil.colors.red('[Error]'), err.toString());
        })
        .pipe(concat('bootstrap-iso.min.css'))
        .pipe(gulp.dest('assets/css/vendor/'));
})

gulp.task("isolate-bootstrap-css", ['minify-bootstrap-css'], function () {
    gutil.log('... Generating isolated bootstrap');
    gulp.src('assets/css/bootstrap-iso.less')
        .pipe(less())
        .pipe(replace('.bootstrap-iso html', ''))
        .pipe(replace('.bootstrap-iso body', ''))
        .pipe(gulp.dest('assets/css/vendor/'));
});

gulp.task("serve", function () {
    gutil.log('... Launching Web browser');
    gutil.log('... Starting Jelyll');
    shell.task([
        "python -m webbrowser 'http://localhost:4000/Type-on-Strap/' && bundle exec jekyll serve --watch"
    ])
});

gulp.task('default', ['js', 'img'], function () {
    return gutil.log('... Gulp is running!');
});