Deeply resolves all promises in a data structure

deepAsync.js

// Arbitrarily nested object containing Promises goes in
// Plain data structure comes out
async function deepAsync (object) {
  // Walk arrays
  if (Array.isArray(object)) {
    return Promise.all(object.map(async item => await deepAsync(item)))

  // Walk objects
  } else if (object instanceof Object) {
    return Object
      .entries(object)
      .reduce(async (carry, [ key, value ]) => {
        return Object.assign({}, carry, { [key]: await deepAsync(value) })
      }, {})

  // Await promise values
  } else if (object instanceof Object && typeof object.then instanceof Function) {
    return deepAsync(await object)

  // Return all others
  } else {
    return object
  }
}

Change sort of deprecated typeof to instanceof.