This method is a Work In Progress. It requires async functionality and returning a Promise to be useful in scripts. See issue #447 for details.
Waits for the event to fire and passes its value into the predicate function. Returns the event data value when the predicate returns true.
|string||null||Name of event to wait for. NOTE: Currently this argument is disregarded, and waitForEvent will always wait for 'close' or 'page' events.|
|function|object||null||Optional. If it's a function, the 'page' event data will be passed to it and it must return true to continue.|