use npmjs from the browser

need.js

console.log('installed: need, crave')
crave = m => fetch(`https://wzrd.in/bundle/${m}@latest/`)
  .then(r => r.text())
  .then(eval)
  .then(() => require(m))
need = m => {crave(m).then(r => {
  window[m] = r
  console.log(`installed: ${m}`)
})}

usage.js

// based on: https://gist.github.com/mathisonian/c325dbe02ea4d6880c4e
// usage once run in the browser (using a bookmarklet: https://bookmarkify.it/7166)

// folktale gets downloaded but not made available globally
crave('folktale').then(console.log) 

// folktale gets installed globally
need('folktale')