Implementing waitFor functionality with phantomjs-node

Question

I have tried and tested - with success - the phantomjs example waitFor. However, I am having difficulty implementing it via the phantomjs-node module primarily because

Answer 1

I've written an alternative for phantomjs-node called phridge. Instead of turning all function calls and assignments into async operations it just executes the whole function inside PhantomJS.

I think your problem could be accomplished like this:

phridge.spawn()
    .then(function (phantom) {
        return phantom.openPage(url);
    })
    .then(function (page) {
        return page.run(selector, function (selector, resolve, reject) {
            // this function runs inside PhantomJS bound to the webpage instance
            var page = this;
            var intervalId = setInterval(function () {
                var hasBeenFound = page.evaluate(function (selector) {
                    return Boolean(document.querySelector(selector));
                }, selector);

                if (hasBeenFound === false &&
                    /* check if there is still some time left  */) {
                    // wait for next interval
                    return;
                }

                clearInterval(intervalId);

                if (hasBeenFound) {
                    resolve();
                } else {
                    reject(new Error("Wait for " + selector + " timeout"));
                }
            }, 100);
        });
    })
    .then(function () {
        // element has been found
    })
    .catch(function (err) {
        // element has not been found
    });