build.js

#! /usr/bin/env node

'use strict'

// BUILD.JS: This file is responsible for building static HTML pages

const fs = require('fs')
const path = require('path')
const Metalsmith = require('metalsmith')
const collections = require('metalsmith-collections')
const feed = require('metalsmith-feed')
const discoverHelpers = require('metalsmith-discover-helpers')
const discoverPartials = require('metalsmith-discover-partials')
const layouts = require('metalsmith-layouts')
const markdown = require('metalsmith-markdown')
const prism = require('metalsmith-prism')
const permalinks = require('metalsmith-permalinks')
const pagination = require('metalsmith-yearly-pagination')
const defaultsDeep = require('lodash.defaultsdeep')
const autoprefixer = require('autoprefixer')
const marked = require('marked')
const postcss = require('postcss')
const fibers = require('fibers')
const sass = require('sass')
const ncp = require('ncp')
const junk = require('junk')
const semver = require('semver')

const githubLinks = require('./scripts/plugins/githubLinks')
const navigation = require('./scripts/plugins/navigation')
const anchorMarkdownHeadings = require('./scripts/plugins/anchor-markdown-headings')
const loadVersions = require('./scripts/load-versions')
const latestVersion = require('./scripts/helpers/latestversion')

// Set the default language, also functions as a fallback for properties which
// are not defined in the given language.
const DEFAULT_LANG = 'en'

// Set up the Markdown renderer that we'll use for our Metalsmith build process,
// with the necessary adjustments that we need to make in order to have Prism
// work.
const renderer = new marked.Renderer()
renderer.heading = anchorMarkdownHeadings
const markedOptions = {
  langPrefix: 'language-',
  renderer
}

// This function imports a given language file and uses the default language set
// in DEFAULT_LANG as a fallback to prevent any strings that aren't filled out
// from appearing as blank.
function i18nJSON (lang) {
  const defaultJSON = require(`./locale/${DEFAULT_LANG}/site.json`)
  const templateJSON = require(`./locale/${lang}/site.json`)

  return defaultsDeep({}, templateJSON, defaultJSON)
}

// This function imports language file for each given locale in array 'localesList'
// and based on it generating locales data, which includes full language name, english language name, locale and link
function generateLocalesData (localesList) {
  return localesList.map(localeEl => {
    const { language, languageEnglishVersion, locale, url } = require(`./locale/${localeEl}/site.json`)
    return { language, locale, url, languageEnglishVersion }
  })
}

// This is the function where the actual magic happens. This contains the main
// Metalsmith build cycle used for building a locale subsite, such as the
// english one.
function buildLocale (source, locale, opts) {
  console.log(`[metalsmith] build/${locale} started`)
  const labelForBuild = `[metalsmith] build/${locale} finished`
  console.time(labelForBuild)
  const metalsmith = Metalsmith(__dirname)

  metalsmith
  // Sets global metadata imported from the locale's respective site.json.
    .metadata({
      site: i18nJSON(locale),
      project: source.project,
      locales: opts.localesData
    })
  // Sets the build source as the locale folder.
    .source(path.join(__dirname, 'locale', locale))
    // site.json files aren't needed in the output dir
    .ignore('site.json')
    .use(withPreserveLocale(opts && opts.preserveLocale))
    // Extracts the main menu and sub-menu links form locale's site.json and
    // adds them to the metadata. This data is used in the navigation template
    .use(navigation(source.project.latestVersions))
    // Defines the blog post/guide collections used to internally group them for
    // easier future handling and feed generation.
    .use(collections({
      blog: {
        pattern: 'blog/**/*.md',
        sortBy: 'date',
        reverse: true,
        refer: false
      },
      blogReleases: {
        pattern: 'blog/release/*.md',
        sortBy: 'date',
        reverse: true,
        refer: false
      },
      blogVulnerability: {
        pattern: 'blog/vulnerability/*.md',
        sortBy: 'date',
        reverse: true,
        refer: false
      },
      knowledgeBase: {
        pattern: 'knowledge/**/*.md',
        refer: false
      },
      guides: {
        pattern: 'docs/guides/!(index).md'
      }
    }))
    .use(pagination({
      path: 'blog/year',
      iteratee: (post, idx) => ({
        post,
        displaySummary: idx < 10
      })
    }))
    .use(markdown(markedOptions))
    .use(githubLinks({ locale, site: i18nJSON(locale) }))
    .use(prism())
    // Set pretty permalinks, we don't want .html suffixes everywhere.
    .use(permalinks({
      relative: false
    }))
    // Generates the feed XML files from their respective collections which were
    // defined earlier on.
    .use(feed({
      collection: 'blog',
      destination: 'feed/blog.xml',
      title: 'Node.js Blog'
    }))
    .use(feed({
      collection: 'blogReleases',
      destination: 'feed/releases.xml',
      title: 'Node.js Blog: Releases'
    }))
    .use(feed({
      collection: 'blogVulnerability',
      destination: 'feed/vulnerability.xml',
      title: 'Node.js Blog: Vulnerability Reports'
    }))
    // Finally, this compiles the rest of the layouts present in ./layouts.
    // They're language-agnostic, but have to be regenerated for every locale
    // anyways.
    .use(discoverPartials({
      directory: 'layouts/partials',
      pattern: /\.hbs$/
    }))
    .use(discoverHelpers({
      directory: 'scripts/helpers',
      pattern: /\.js$/
    }))
    .use(layouts())
    // Pipes the generated files into their respective subdirectory in the build
    // directory.
    .destination(path.join(__dirname, 'build', locale))

  // This actually executes the build and stops the internal timer after
  // completion.
  metalsmith.build((err) => {
    if (err) { throw err }
    console.timeEnd(labelForBuild)
  })
}

// This plugin reads the files present in the english locale that are missing
// in the current locale being built (requires preserveLocale flag)
function withPreserveLocale (preserveLocale) {
  return (files, m, next) => {
    if (preserveLocale) {
      const path = m.path('locale/en')
      m.read(path, (err, newfiles) => {
        if (err) {
          console.error(err)
          return next(err)
        }

        Object.keys(newfiles).forEach((key) => {
          if (!files[key]) {
            files[key] = newfiles[key]
          }
        })
        next()
      })
    } else {
      next()
    }
  }
}

// This function builds the static/css folder for all the Sass files.
function buildCSS () {
  console.log('[sass] static/css started')
  const labelForBuild = '[sass] static/css finished'
  console.time(labelForBuild)

  const src = path.join(__dirname, 'layouts/css/styles.scss')
  const dest = path.join(__dirname, 'build/static/css/styles.css')

  const sassOpts = {
    file: src,
    fiber: fibers,
    outFile: dest,
    outputStyle: process.env.NODE_ENV !== 'development' ? 'compressed' : 'expanded'
  }

  fs.mkdir(path.join(__dirname, 'build/static/css'), { recursive: true }, (err) => {
    if (err) {
      throw err
    }

    sass.render(sassOpts, (error, result) => {
      if (error) {
        throw error
      }

      postcss([autoprefixer]).process(result.css, { from: src }).then(res => {
        res.warnings().forEach(warn => {
          console.warn(warn.toString())
        })

        fs.writeFile(dest, res.css, (err) => {
          if (err) {
            throw err
          }

          console.timeEnd(labelForBuild)
        })
      })
    })
  })
}

// This function copies the rest of the static assets to their subfolder in the
// build directory.
function copyStatic () {
  console.log('[ncp] build/static started')
  const labelForBuild = '[ncp] build/static finished'
  console.time(labelForBuild)
  fs.mkdir(path.join(__dirname, 'build/static'), { recursive: true }, (err) => {
    if (err) {
      throw err
    }

    ncp(path.join(__dirname, 'static'), path.join(__dirname, 'build/static'), (error) => {
      if (error) {
        return console.error(error)
      }
      console.timeEnd(labelForBuild)
    })
  })
}

function getSource (callback) {
  // Loads all node/io.js versions.
  loadVersions((err, versions) => {
    const source = {
      project: {
        versions,
        latestVersions: {
          current: latestVersion.current(versions),
          lts: latestVersion.lts(versions)
        },
        blacklivesmatter: {
          visible: true,
          text: '#BlackLivesMatter',
          link: '/en/black-lives-matter/'
        },
        banner: {
          visible: false,
          text: 'Help us decide the future of Unhandled Rejections',
          link: 'https://www.surveymonkey.com/r/FTJM7YD'
        }
      }
    }
    if (semver.gt(source.project.latestVersions.lts.node, source.project.latestVersions.current.node)) {
      // If LTS is higher than Current hide it from the main page
      source.project.latestVersions.hideCurrent = true
    }

    callback(err, source)
  })
}

// This is where the build is orchestrated from, as indicated by the function
// name. It brings together all build steps and dependencies and executes them.
function fullBuild (opts) {
  const { selectedLocales, preserveLocale } = opts
  getSource((err, source) => {
    if (err) { throw err }

    // Executes the build cycle for every locale.
    fs.readdir(path.join(__dirname, 'locale'), (e, locales) => {
      if (e) {
        throw e
      }
      const filteredLocales = locales.filter(file => junk.not(file) && (selectedLocales ? selectedLocales.includes(file) : true))
      const localesData = generateLocalesData(filteredLocales)
      filteredLocales.forEach((locale) => {
        buildLocale(source, locale, { preserveLocale, localesData })
      })
    })
  })
}

// Starts the build if the file was executed from the command line
if (require.main === module) {
  const preserveLocale = process.argv.includes('--preserveLocale')
  const selectedLocales = process.env.DEFAULT_LOCALE ? process.env.DEFAULT_LOCALE.toLowerCase().split(',') : process.env.DEFAULT_LOCALE
  // Copy static files
  copyStatic()
  // Build CSS
  buildCSS()
  fullBuild({ selectedLocales, preserveLocale })
}

exports.getSource = getSource
exports.fullBuild = fullBuild
exports.buildCSS = buildCSS
exports.buildLocale = buildLocale
exports.copyStatic = copyStatic
exports.generateLocalesData = generateLocalesData