p_limit 1.0.0

Run multiple promise-returning & async functions with limited concurrency.

Install

flutter pub add p_limit

Usage

import 'package:p_limit/p_limit.dart';

void main() async {
  final limit = PLimit<string>(1);
  final input = [
    limit(() => fetchSomething('foo')),
    limit(() => fetchSomething('bar')),
    limit(() => doSomething())
  ];
  // Only one promise is run at once
  final results = await Future.wait(input);
  print(results);

  limit.
}

API

PLimit(concurrency)

Returns a limit function.

concurrency

Type: number
Minimum: 1
Default: Infinity

Concurrency limit.

limit(fn)

Returns the promise returned by calling fn().

fn

Type: Function

Promise-returning/async function.

limit.activeCount

The number of promises that are currently running.

limit.pendingCount

The number of promises that are waiting to run (i.e. their internal fn was not called yet).

limit.clearQueue()

Discard pending promises that are waiting to run.

This might be useful if you want to teardown the queue at the end of your program's lifecycle or discard any function calls referencing an intermediary state of your app.

Note: This does not cancel promises that are already running.

FAQ

How is this different from the async_task package?

This package is only about limiting the number of concurrent executions, while async_task is a fully featured queue implementation similar to classic thread pools and with lots of different options.

Related

• async_task - Asynchronous tasks and parallel executors

Additional information

If you have an issue, let me know on Github issues