debonet / es6condition

Wait/Signal/Broadcast Promise-based Condition Variables for event synchronization

es6condition.js

Simple, dependency-free Condition Variables for ES6 event synchronization.

INSTALLATION

npm install @debonet/es6condition

OVERVIEW

es6condition provides a Promises-based condition object for synchronizing events by allowing an event to wait on a signal before proceeding

TYPICAL USAGE

wait(), signal(), and broadcast() have the typical Condition Variable semantics and can be used as Promises or with async/await syntax, e.g.:

signal

signal() releases the first event that is waiting on the Condition. Here's an example:

	const cond = new Condition();

	setTimeout(	() => {
		console.log("Hello,");
		cond.signal();
	}, 100);

	// wait until a signal is sent
	await cond.wait();
	
	console.log("World");

and generate an output:

Hello,
World

broadcast

broadcast() releases the all events that are waiting on the Condition. Here's an example:

const cond = new Condition();

setImmediate(async () => {
	cond.wait().then(() => { console.log("Myself," )});
});

setImmediate(async () => {
	await cond.wait();
	console.log("and I");
});

setImmediate(async () => {
	cond.broadcast();
	console.log("Me,");
});

and generate an output:

Me,
Myself,
and I

Condition member functions

wait()

fpWait()

Waits until a signal has been received. Technically speaking it returns a promise that resolves when a signal() on the condition variable has been received

signal()

release()

fSignal()

fRelease()

Sends a signal to the first event waiting on the condition variable. Technically speaking, it resolves the promise generated by the call to wait()

broadcast()

signalAll()

releaseAll()

fSignalAll()

fReleaseAll()

fBroadcast()

Sends a signal to every event waiting on the condition variable. Technically speaking, it resolves the promise generated by the call to wait()

APPENDIX

definition of sleep() used in the example above

	function sleep( dtm ){
		return new Promise( fOk => setTimeout( fOk, dtm ));
	}