promise-poller.js

/**
 * repeats a check until the check is true or the timeout is reached
 * returns a promise that we can return to mocha
 */
function promisePoller(condition,
    interval = 10,
    timeout = 1000,
    onTimeout = new Error("Timed out")) {
    return new Promise(function (resolve, reject) {
        function check() {
            setTimeout(() => {
                if (condition()) resolve()
                else check()
            }, interval)
        }

        setTimeout(() => { reject(onTimeout) }, timeout)
        check()
    })
}