map-p

Map over an (eventual) list of promises

map(list: Promise<Array<any>>|Array<any>, mapper: Function(any, int) -> Promise<any>|Any) -> Promise<Array<any>>

Explanation

This module is written to encourage a style focusing on promises as eventual values rather than as flow control, and to show the dependency between values rather than the dependency between functions, encouraging decoupling of functions that don't need to be coupled.

This is much like Bluebird's map function, though it does not have the concurrency controls.

It resolves its parameters, so it can both take an eventual list, and deal with eventual values in the list.

Use

The identity transform:

map(list, (e, i) => e)

A more complete example showing eventual values:

const listP = Promise.resolve([1, 2, Promise.resolve(3)])
const mapped = map(listP, e => {
    e * 2
})

mapped.then(console.warn)

This prints [2, 4, 6], having handled both the promise of an array and a promise of one of the values in the list.