index.js

'use strict'

const fastifyPlugin = require('fastify-plugin')
const { readFile } = require('fs')
const { resolve } = require('path')
const engine = require('pug')

function fastifyPug(fastify, opts, next) {
  fastify.decorateReply('locals', {})
  fastify.decorateReply('render', render)
  fastify.decorateReply('view', render)

  const cache = {}
  const templatesDir = resolve(opts.views)
  const fileEnding = '.pug'

  let fallbackTempateDir
  if (opts.fallbackViews) {
    fallbackTempateDir = resolve(opts.fallbackViews)
  }

  function render(view, options) {
    let locals = { ...opts, ...options }
    locals = { ...locals, ...this.locals }

    if (typeof opts.filename === 'function') {
      locals = { ...locals, filename: opts.filename(view) }
    }

    if (!view.includes(fileEnding)) {
      view += fileEnding
    }
    const cachedView = cache[view]

    if (cachedView && process.env.NODE_ENV === 'production') {
      const html = cachedView(locals)
      setContentTypeHeader(this)
      this.send(html)
    } else {
      readFile(`${templatesDir}/${view}`, 'utf8', readFileCallback(this, templatesDir, fallbackTempateDir, view, locals))
    }
  }

  function readFileCallback(that, templatesDir, fallbackTempateDir, view, locals) {
    return function readFileCallbackInternal(error, template) {
      if (error && fallbackTempateDir) {
        readFile(`${fallbackTempateDir}/${view}`, 'utf8', readFileCallback(that, templatesDir, null, view, locals))
        return
      } else if (error) {
        that.send(error)
        return
      }
      const compiledTemplate = engine.compile(template, locals)
      cache[view] = compiledTemplate
      setContentTypeHeader(that)
      that.send(compiledTemplate(locals))
    }
  }
  next()
}

function setContentTypeHeader(that) {
  if (!that.getHeader('content-type')) {
    that.header('Content-Type', 'text/html; charset=UTF-8')
  }
}

const metadata = {
  fastify: '>=1.0.0',
  name: 'fastify-pug'
}

exports = module.exports = fastifyPlugin(fastifyPug, metadata)