index.js

const { send } = require('micro')
const matchRoute = require('my-way')

const icons = require('./icons.js')
const serveHomepage = require('./home.js')

const serveIcon = (req, res, params) => {
  const { name, color } = params

  if (icons[name]) {
    res.setHeader('Content-Type', 'image/svg+xml')
    res.setHeader('Cache-Control', 'public, max-age=86400, s-maxage=31536000, stale-while-revalidate=604800')
    return send(res, 200, transformSVG(icons[name].svg, { fill: color }))
  }

  send(res, 404)
}

const serveRedirect = (req, res, params) => {
  const name = params.name.split('.')[0]

  if (icons[name]) {
    const { color } = require('url').parse(req.url, true).query
    res.setHeader('Location', `/${name}/${color}`)
    return send(res, 301)
  }

  send(res, 404)
}

const transformSVG = (svgString, { fill }) => {
  if (fill) {
    svgString = svgString.replace(/^<svg /, `<svg fill="#${fill}" `)
  }
  return svgString
}

module.exports = (req, res) => {
  if (req.method !== 'GET') {
    return send(res, 403)
  }

  if (req.url === '/') {
    res.setHeader('Cache-Control', 'public, max-age=3600, s-maxage=2592000')
    return serveHomepage(req, res)
  }

  const redirectParams = matchRoute('/icons/:name', req.url)

  if (redirectParams) {
    return serveRedirect(req, res, redirectParams)
  }

  const iconParams = matchRoute('/:name/:color?', req.url)
  if (iconParams) {
    return serveIcon(req, res, iconParams)
  }

  send(res, 404)
}