n-barrier

Simple barrier implementation for syncing multiple asyncronouse tasks.

Provides two barrier implementations:

• nBarrier which wait for n tasks to reach their .wait() instruction
• pBarrier which waits for passed in promisses to resolve

installation

npm install n-barrier

usage

nBarrier

Let n tasks wait for each other before continuing execution.

example

const { nBarrier } = require('n-barrier')
const barrier = nBarrier(3) // barrier which wait for 3 tasks before opening
 
const startTask = time => setTimeout(() => {
  await barrier.wait() // tasks wait here before 3 tasks in total reach this point
  console.log('finished')
}, time)
 
startTask(0)
startTask(0)
startTask(1000)
// no console output for the first 1000ms then
// all 'finished' messages will be logged at once

pBarrier

pBarrier works similar to Promise.all but you will get back a barrier instance with a wait() method you can pass around to await the resolvement at multiple locations.

const { pBarrier } = require('n-barrier')
 
const startTask = time => new Promise(resolve => setTimeout(() => {
  resolve()
}, time))
 
const asyncTaskWithBarrier = async barrier => {
  // ...do some stuff
  await barrier.wait() // wait for the other tasks to finish
  console.log('asyncTaskWithBarrier continues')
}
 
const barrier = pBarrier(startTask(0), startTask(0), startTask(1000))
 
asyncTaskWithBarrier(barrier) // starts another aync task
 
await barrier.wait()
console.log('all tasks finished') // will only be logged after 1000ms (after each promise resolved)