last-one-wins

last-one-wins

Make sure the last sync call to an async function is executed after all previous ones have finished

npm install last-one-wins

Usage

var low = require('last-one-wins')

var pick = low(function (num, cb) {
  setTimeout(function () {
    console.log('picked', num)
    cb()
  }, Math.floor(Math.random() * 100))
})

pick(1)
pick(2)
pick(3)
pick(4)
pick(5) // this one will always win since its called the last

Calling the above will print out

picked 1
picked 5

API

var fn = low(asyncWorker)

Wrap a async function to make sure that the last sync call to that function is executed after any previous calls. Note that not all calls are executed - only the last one is guaranteed to be executed.

fn and asyncWorker should have the signature (value, cb)

Use with leveldb

This module is useful if you want sync a value to a leveldb and want to make sure the latest version of that value is the one written. For example

var update = low(function (val, cb) {
  db.put('my-key', val, cb)
})

update('a')
update('b')
update('c')

Is guaranteed to always write c to the key my-key.

License

MIT