This perf tests measures the speed of monomorphic (inline-cache hit) vs megamorphic (megamorphic cache hit and miss) read on both javascript as well as DOM objects.

DOM access is inherently megamorphic. This perf-tests attempts to prove that caching the methods on the DOM and invoking them using .call() is faster than using the megamorphic property lookup.

    // Cache the getter only once.
    const Node_parentNode_getter = Object.getOwnPropertyDescriptor(Node.prototype, 'parentNode').get;; // Is the fastest way to access DOM.
    domNode.parentNode; // is megamorphic and hence slower than the line above.

This approach seems to hold in all browser (except for chrome due to issue 8820).

Further reading:


Browser OBJ_mega/OBJ_mono OBJ_call/OBJ_mono DOM_mega/DOM_mono DOM_call/DOM_mono
computing... computing... computing... computing... computing...
-- historic for comparison data --
Chrome/72.0.3626.96 Safari/537.36 181.7 5.2 2.9 3.5
Gecko/20100101 Firefox/64.0 13 0.6 6.6 1.2
Version/12.2 Safari/605.1.15 24.4 2 9.1 3