limiter-component

limiter

Limits the rate of function calls to one per period. It delays but does not throttle the calls. Useful when your codes needs to behave well when calling rate limited API.

If you need something more flexible use rate limiter

Installation

$ npm install --save limiter-component

Usage

Create limiter with desired interval setting. Call trigger passing a function that you want to limit.

var limiter = require('limiter'),
	l = limiter(500); // interval in millis

function doThis() {
  // this is called at most twice per second
}

function doThat() {
  // you can rate limit different functions
}


l.trigger(doThis);
l.trigger(doThat);
l.trigger(doThis);
l.trigger(function() {
	l.penalty(); // wait a bit longer the next time
});
l.trigger(doThat);
l.trigger(function() {
	l.skip(); // don't wait at all the next time
});
l.trigger(doThis);

// you can also wait for the trigger using Promises

await l.trigger(); // note that `fn` is optional
// trigger has been resolved

API

limiter(interval, [penaltyInterval])

Create limiter with desired interval (in millis). Optional penaltyInterval is used instead of interval if limiter.penalty() has been called at least once since last limited function has been triggered.

trigger(fn)

Add fn to limiter queue. It will be called when interval elapsed since another function from the queue was called. Returns a promise, which is resolved when fn is called.

penalty()

Make limiter use penaltyInterval before triggering next function.

skip()

Make limiter trigger next function immediately.

cancel()

Empty limiter queue. Remove all pending trigger request. No methods from the queue is called after cancel.

License

MIT