JSFiddle - React, Tailwind, and code Playground
by sanford
HTML
<PRE id="result"></PRE>
JavaScript
var myObject = {a: 'one', b: 'two', c: 3};
$('result').appendText(Object.keyOf(myObject, 'two')+'\n'); // returns 'b'
$('result').appendText(Object.keyOf(myObject, 3)+'\n' ); // returns 'c'
$('result').appendText( Object.keyOf(myObject, 'four')+'\n' ); // returns null, according to docs s/b false