Throttler

Runs tasks one at a time while keeping at least the configured interval between starts.

Use Throttler when every submitted task should run, but starts should be spaced over time. It does not drop intermediate calls.

Import

import { Duration } from '@haskou/value-objects';
import { ThrottleInterval, Throttler } from '@haskou/flow';

Signature

class Throttler

Constructor

constructor(interval: number | Duration | ThrottleInterval)

Number inputs are interpreted as milliseconds.

Validation

The interval accepts a millisecond number, Duration, or ThrottleInterval. Internally, the interval is stored as ThrottleInterval.

Throws

This class can throw:

• InvalidThrottlerIntervalError
• any error thrown by a throttled task

Methods

Method	Description
run(task)	Queues a task and runs it when the throttle interval allows.
waitUntilIdle()	Resolves when the internal queue is idle.

Example

import { Throttler } from '@haskou/flow';

const throttler = new Throttler(Duration.fromMilliseconds(100));

await Promise.all([
  throttler.run(() => callApi('a')),
  throttler.run(() => callApi('b')),
]);

await throttler.waitUntilIdle();

Notes

• Throttler uses an internal one-at-a-time queue.
• The first task runs immediately.
• Later tasks wait until the minimum interval has elapsed.
• The stored ThrottleInterval uses TimerDelay at the timer boundary.
• Unlike Debouncer, every task is eventually run unless its task rejects.

Related

• Debouncer
• RateLimiter
• Queue