const pipe = require('it-pipe')

const result = await pipe(
  // A source is just an iterable, this is shorthand for () => [1, 2, 3]
  [1, 2, 3],
  // A transform takes a source, and returns a source.
  // This transform doubles each value asynchronously.
  function transform (source) {
    return (async function * () { // A generator is async iterable
      for await (const val of source) yield val * 2
    })()
  },
  // A sink, it takes a source and consumes it, optionally returning a value.
  // This sink buffers up all the values from the source and returns them.
  async function collect (source) {
    const vals = []
    for await (const val of source) {
      vals.push(val)
    }
    return vals
  }
)

console.log(result) // 2,4,6