In this article you find a demonstration of the xml parser. type in some xml and see the resulting data as JSON. The xml is parsed on every keystroke and still you will see that the result is generated very fast.
You can also try to break your XML to see the error tollerance of this parser. select the simplefied mode, to see how the result will be affected.(it is the same result as in PHPs SimpleXMLParser). It you like it, install it from npm.