File downloading
You can try by running this code at your console:
deno run https://mega.js.org/demos/downloading-demo.js
import { getLoggedInStorage } from './logging-in-demo.js'
const storage = await getLoggedInStorage()
console.log('Choose one of the following files:')
console.log(storage.root.children.filter(e => !e.children).map(e => e.name))
const filename = prompt('Enter a file name (case sensitive):')
const file = storage.find(filename)
if (!file) throw Error('File not found!')
const data = await file.downloadBuffer()
await Deno.writeFile(file.name, data)