nodejs Async's whilst

Question

Greeting all,

I want to call a function repeatedly, but wanted each call to run only when the previous call is completed. Does the Async's whilst fit what I need? Or do the calls happen in parallel?

Thanks!

Gary

Answer 1

Whilst will do what you need, it runs each function in series. Before each run it will do the "test" function to make sure it should run again.

Their example:

var count = 0;

async.whilst(
    function () { return count < 5; },
    function (callback) {
        count++;
        setTimeout(callback, 1000);
    },
    function (err) {
        // 5 seconds have passed
    }
);

Answer 2

As Chad noted, Async's whilst will do the job.

You may want to consider Async's until (inverse of whilst). Both do the same job however the key difference is:

• async.whilst will call the function each time the test passes
• async.until will call the function each time the test fails