async-single

run an async function but only once at a time.

also, debounce the function with timers.

example

var AsyncSingle = requrie('async-single')

var as = AsyncSingle(function (value, cb) {
  fs.writeFile(filename, value, cb) //or some other async thing!
})

//write as often as you like.
//not every write will happen,
//but it will write every so often
as.write('hello world')

as.write('again!')

//when you close, it will finish off any writes!
as.close(function () {...})

exploration of async programming style, by solving the same problem the same way several times.

The problem, is to take an async function, and wrap it to that it is only called once at a time.

var async = Single(function (value, cb) {
  ThisMayTakeSomeTime(function () {
    //...
    cb()
  })
})

async.onDrain = function () {
  //called when there is no longer something waiting to write
}

async.write(value)

if you call many times quickly, it may write the first time, but then wait until that succeeds before writing the latest value. If you have three quick writes async.write(1);async.write(2);async.write(3); then the first write is fired, then if the async operation is still in flight before the others are received, the value of the last write will be performed.

(in practice, we would probably want to delay the first write so that quick writes get bundled! but we are keeping this simple as an exercise!)

License

MIT