Find and inject libraries from cdnjs by name

console.inject.js

/* jshint asi: true, esnext: true */

(() => {
  'use strict'

  const BOLD = 'font-weight: bold;',
        LINK = 'text-decoration: underline; color: #03d',
        RESET = 'font-weight: normal; text-decoration: none; color: black; background-color: white; display: inline'

  // ----------------------------------------------------------

  const findElement = (tag, attr = {}) => !!document.querySelector(tag + Object.keys(attr).map(k => `[${k}="${attr[k]}"]`).join(''))

  // ----------------------------------------------------------

  const EL = (tag, attr = {}) => new Promise((onload, onerror) => {
    const e = Object.assign(document.createElement(tag), attr, { onload, onerror })
    document.body.appendChild(e)
  })

  // ----------------------------------------------------------

  console.inject = (library, force) => new Promise((resolve, reject) => {
    if (!force || findElement('script', { 'data-query': library })) {
      console.info(`Library %c"${library}"%c already injected`, BOLD, RESET)
      resolve(library)
    }

    // https://api.cdnjs.com/libraries?search=url&fields=name,description,version.,author,homepage,license,repository,keywords,autoupdate,latest,assets
    const url = `https://api.cdnjs.com/libraries?search=${library}`

    fetch(url)
      .then(response => response.ok && response.json())
      .then(json => {
        const { total, results } = json

        const lib_re = RegExp(`^${library}(\\.js)?$`, 'i')

        const m = results.find(r => lib_re.test(r.name))

        if (m) {
          const src = m.latest.replace(/^http:/, 'https:')

          EL('script', {
            src,
            'data-query': library
          })
            .then(
              () => {
                console.info(`Library %c"${library}"%c injected from %c${src}%c`, BOLD, RESET, LINK, RESET)
                resolve(library)
              },
              () => {
                console.warn(`Library %c"${library}"%c from %c${src}%c failed on load!`, BOLD, RESET, LINK, RESET)
                reject(library)
              }
            )
        } else {
            console.warn(`Library %c"${library}"%c not found!`, BOLD, RESET)
            reject(library)
          }
      })
  })

})()