JavaScript Async Iterators
Introduction
An async function is one that returns a promise. await yields to the caller until the promise resolves and then continues with the result.
An iterator allows the collection to be looped through with a for-of loop.
An async iterator is a collection where each iteration is a promise which can be awaited using a for-await-of loop.
Async iterators are a stage 3 proposal. They are in Chrome Canary 60 with --harmony-async-iteration
Syntax
- async function* asyncGenerator() {}
- yield await asyncOperationWhichReturnsAPromise();
- for await (let result of asyncGenerator()) { /* result is the resolved value from the promise */ }
Remarks
An async iterator is a declarative pull stream as opposed to an Observable's declarative push stream.
