Use Promise to wait until polled condition is satisfied

Question

I need to create a JavaScript Promise that will not resolve until a specific condition is true. Let\'s say I have a 3rd party library, and I need to wait until a certain da

Answer 1

A small variation would be to use a named IIFE so that your code is a little more concise and avoids polluting the external scope:

function ensureFooIsSet() {
    return new Promise(function (resolve, reject) {
        (function waitForFoo(){
            if (lib.foo) return resolve();
            setTimeout(waitForFoo, 30);
        })();
    });
}