build.js

'use strict'

const autoprefixer = require('autoprefixer')
const browserify = require('browserify')
const buffer = require('vinyl-buffer')
const concat = require('gulp-concat')
const cssnano = require('cssnano')
const fs = require('fs')
const svgo = require('gulp-svgo')
const map = require('map-stream')
const merge = require('merge-stream')
const mkdirp = require('mkdirp')
const path = require('path')
const postcss = require('gulp-postcss')
const postcssCalc = require('postcss-calc')
const postcssImport = require('postcss-import')
const postcssUrl = require('postcss-url')
const postcssVar = require('postcss-custom-properties')
const terser = require('gulp-terser')
const gulp = require('gulp')

module.exports = (src, dest) => {
  const opts = { base: src, cwd: src }
  const postcssPlugins = [
    postcssImport(),
    postcssUrl([
      {
        filter: '**/~typeface-*/files/*',
        url: (asset) => {
          const relpath = asset.pathname.substr(1)
          const abspath = path.resolve('node_modules', relpath)
          const basename = path.basename(abspath)
          const destpath = path.join(dest, 'font', basename)
          if (!fs.existsSync(destpath)) {
            const dirname = path.dirname(destpath)
            if (!fs.existsSync(dirname)) {
              mkdirp.sync(dirname)
            }
            fs.copyFileSync(abspath, destpath)
          }
          return path.join('..', 'font', basename)
        }
      }
    ]),
    postcssVar(),
    postcssCalc(),
    autoprefixer(),
    cssnano({ preset: 'default' })
  ]

  return merge([
    gulp
      .src('js/+([0-9])-*.js', opts)
      .pipe(terser())
      .pipe(concat('js/site.js')),

    gulp
      .src('js/vendor/*.js', Object.assign({ read: false }, opts))
      .pipe(
        // see https://gulpjs.org/recipes/browserify-multiple-destination.html
        map((file, next) => {
          file.contents = browserify(file.relative, {
            basedir: src,
            detectGlobals: false
          }).bundle()
          next(null, file)
        })
      )
      .pipe(buffer())
      .pipe(terser()),

    gulp.src('css/site.css', opts).pipe(postcss(postcssPlugins)),

    gulp.src('font/*.woff*(2)', opts),

    gulp.src('img/**', opts).pipe(svgo()),

    gulp.src('helpers/*.js', opts),

    gulp.src('layouts/*.hbs', opts),

    gulp.src('partials/*.hbs', opts)
  ]).pipe(gulp.dest(dest))
}