async-iterator-from

Create async iterators from Arrays, EventEmitters, and Streams

Impractical Example

import { AsyncIterator } from 'async-iterator-from';
import { forAwaitEach } from 'iterall';

const array = [];
const iterator = AsyncIterator.fromArray(array);

forAwaitEach(iterator, value => {
  console.log(value);
});

array.push('a');
// a
array.push('b');
// b

RethinkDB Changefeed Example

import rdash from 'rethinkdbdash';
import { AsyncIterator } from 'async-iterator-from';
import { forAwaitEach } from 'iterall';

const r = rdash();
const array = [];
const iterator = AsyncIterator.fromArray(array);

forAwaitEach(iterator, value => {
  console.log(value);
});

r.table('foo').changes().run().then(cursor => {
  return cursor.each((error, change) => {
    if (error) {
      return iterator.throw(error);
    }
    array.push(change);
  });
});

API

IteratorOptions

Iterator options are the same for all methods and are described below.

• [options.debounce] {Number} Adds a debounce time in ms for new data to be added to the queue.
• [options.onThrow] {Function} Function to be called when the throw method is called. Takes the error thrown as its only argument.
• [options.onReturn] {Function} Function to be called when the return method is called.
• [options.onNext] {Function} Function to be called when the next method is called.
• [options.onPush] {Function} Function to be called when a new value is pushed to the queue. Takes the value as its only argument.
• [options.onEnd] {Function} Function to be called when the throw or return methods are called.

AsyncIterator ([values] [, options])

Creates a new AsyncIterator

Parameters

• [values=[]] {Array} An array to pull the initial values of the iterator from. Additionally, the push method of the values array will be overriden to allow additional values to be added to the iterator.
• [options] {IteratorOptions} Options for iterator setup.

.fromArray (values [, options])

Creates a new AsyncIterator from an Array. This is a convienience method and is the equivalent of calling new on the AsyncIterator class. Can also be imported with import { fromArray } from 'async-iterator-from'

Parameters

• values {Array} An array to pull the initial values of the iterator from. Additionally, the push method of the values array will be overriden to allow additional values to be added to the iterator.
• [options] {IteratorOptions} Options for iterator setup.

.fromEvent (emitter, event [, options])

Creates a new AsyncIterator from an EventEmitter. Can also be imported with import { fromEvent } from 'async-iterator-from'

Parameters

• emitter {EventEmitter} EventEmitter to listen on for data.
• event {String} event name to listen for.
• [options] {IteratorOptions} Options for iterator setup.

.fromStream (stream [, options])

Creates a new AsyncIterator from an EventEmitter. Can also be imported with import { fromStream } from 'async-iterator-from'

Parameters

• stream {Stream} Stream to listen on for data.
• [options] {IteratorOptions} Options for iterator setup.