gulpfile.js

// Modules
const gulp = require('gulp'),
      sass = require('gulp-sass'),
      rename = require('gulp-rename'),
      concat = require('gulp-concat'),
      concatcss = require('gulp-concat-css'),
      minifycss = require('gulp-clean-css'),
      htmlmin = require('gulp-htmlmin'),
      imagemin = require('gulp-imagemin'), uglify = require('gulp-uglify'), del = require('del'),
      runSeq = require('run-sequence'),
      source = require('vinyl-source-stream'),
      vbuffer = require('vinyl-buffer'),
      sourcemaps = require('gulp-sourcemaps'),
      ts = require('gulp-typescript'),
      tsProject = ts.createProject('tsconfig.json'),
      nunjucksRender = require('gulp-nunjucks-render')
      data = require('gulp-data');

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

gulp.task('build-markup', () => {
  return gulp.src('src/njk/*.njk')
    // Add data
    .pipe(data(() => {
      return require('./src/njk/data.json')
    }))
    // Render nunjucks templates
    .pipe(nunjucksRender({
      path: ['src/njk/templates']
    }))
    // Minify
    .pipe(htmlmin({
        collapseWhitespace: true,
        removeComments: true,
        removeEmptyAttributes: true,
        removeRedundantAttributes: true,
        removeAttributeQuotes: true
      }))
    // Output
    .pipe(gulp.dest('dist'));
});

gulp.task('build-styles', () => {
  gulp.src('src/scss/**/*.@(css|scss)')
    // Compile SASS
    .pipe(sass().on('error', sass.logError))
    // Concat
    .pipe(concatcss('app.css'))
    // Save non minified
    .pipe(gulp.dest('dist/css'))
    // Minify
    .pipe(minifycss())
    // Rename
    .pipe(rename('app.min.css'))
    // Output;
    .pipe(gulp.dest('dist/css'));

  // Copy fonts
  return gulp.src('src/fonts/**/*')
    .pipe(gulp.dest('dist/fonts'));
});

gulp.task('build-scripts', () => {
  // Compile Typescript
  tsProject.src()
    .pipe(tsProject())
    .js.pipe(gulp.dest('dist/js'))
    .pipe(concat('app.js'))
    .pipe(gulp.dest('dist/js'))
    .pipe(rename('app.min.js'))
    .pipe(uglify())
    .pipe(gulp.dest('dist/js'));

  // Copy libraries
  return gulp.src('src/js/lib/**/*.js')
    .pipe(gulp.dest('dist/js/lib'));
});

gulp.task('build-images', () => {
  return gulp.src('src/images/**/*')
    // Minify
    .pipe(imagemin())
    // Output
    .pipe(gulp.dest('dist/images'));
});

gulp.task('build-downloads', () => {
  return gulp.src('src/downloads/**/*')
    // Output
    .pipe(gulp.dest('dist/downloads'));
});

// Build all
gulp.task('build', () => {
  runSeq('clean', ['build-markup', 'build-styles', 'build-scripts', 'build-images', 'build-downloads']);
});

// Default to build all
gulp.task('default', ['build']);