onlyWhen - run a function with its original arguments once a condition is met.

onlyWhen.js

/**
 * Creates a wrapped version of a funtion that will run with the original
 * arguments, once a condition is met. If the condition is not met, it will
 * be checked on a set interval until it is met.
 *
 * @param  {Boolean}  condition     function you expect to eventually return a truthy value
 * @param  {Function} func          original function to resolve
 * @param  {Number}   interval      time to wait between checks
 * @return {Function}               wrapped function you call can call as it it was the original function
 */
function onlyWhen(condition, func, interval) {
    var _this;
    var _arguments;

    function attemptToResolve() {
        if (!condition()) {
            setTimeout(attemptToResolve, interval || 100);
        } else {
            func.apply(_this, _arguments);
        }
    }

    return function () {
        _this = this;
        _arguments = arguments;

        attemptToResolve();
    };
}