Generators

Methods

(static) fromStream(eventSource, dataEventopt, closeEventopt) → {iteration}

Source:
import {fromStream} from 'async_iter/pipeline/from_stream' # pipeline version
import {fromStream} from 'async_iter/from_stream' # conventional version

Returns an iterator, that emits as per the dataEvent of the eventSource

Parameters:
Name Type Attributes Default Description
eventSource EventEmitter

An object that supports the on and removeListener function
dataEvent String <optional>
 data

The main dataEvent name to listen to
closeEvent String <optional>
 close

When this event emits, the iteration is stopped
Returns:

An iterable source

Type
iteration

(static) interval(period, cancel) → {Iterable}

Source:
import {interval} from 'async_iter/interval'

Returns an async iterator the will emit every period milliseconds

  • The iterator will block its emitted values, until the consumer has consumed the item, therefore there is no racing of producer to consumer.
  • The iteration stops, when the consumer breaks, stop the iteration or the cancel promise is resolved
Parameters:
Name Type Description
period Number

the time in milliseconds the iterator emits
cancel Promise

A promise that when it resolves, causes the interval to stop generating values
Returns:

An iteration that emits as per the interval period

Type
Iterable

(static) pump(fn, marker=opt) → {Iteratable}

Source:
import {pump} from 'async_iter/pump'

pump allows for the 'pushing' of values into an async iterator consumer

The push operation returns a promise, that resolves when the consuming iteration has consumed the item

This function follows the convention of a pushed iterator interface (next, throw, return).

If the code pushing values, does not await the return promise, the values are then queued for processing by the consumer as it pulls in the values

The callback is not invoked, until the first item is pulled from the iteration

Example
import {pump} from 'async_iter'

// Create a push based iteration set
const items = await pump(target => {
  //Values can be push to the iteration
  await target.next(1) // if you dont 'await' the values will be queued.
  await target.next(2)
  await target.next(3)
  // If you want to push an 'error' to the consumer
  // await target.throw(new Error('This is an error'))
  await target.return()
})

for await (const item of items)
  console.log(item)
Parameters:
Name Type Attributes Description
fn pumpCallback

this is a function that will async pump values into the interator
marker= String <optional>
Returns:

A standard async iterator that can consume the generated values

Type
Iteratable

(static) range(optsopt) → {Iterable}

Source:
import {range} from 'async_iter/range' # conventional version

Returns an iterator that iterates from start to end (inclusive) by step amounts

Parameters:
Name Type Attributes Description
opts Object <optional>

the optional start, end and step values for the generation

Properties
Name Type Attributes Default Description
start Object <optional>
 0

the starting number for the iteration
end Object <optional>
 Number.POSITIVE_INFINITY

the end number for the iteration
step Object <optional>
 1

the increment for the iteration
Returns:

An iteration for the specified range

Type
Iterable

(static) spawn(command, argsopt, optionsopt) → {iteration}

Source:

Adapter for the nodejs function child_process.spawn. Mapping the stdout and stderr to an iterable

Parameters:
Name Type Attributes Description
command string

The command to run
args Array.<string> <optional>

The arguments to supply to the command
options object <optional>

Any options to be passed thru to child_process.spawn
Returns:

An iterable source that contain an object with one of 2 keys (stdout or stderr)

Type
iteration