Quickly filter an object by keys - Code Review Stack Exchange
unfiltered || (!unfiltered && keys[key]) is redundant you can just do unfiltered || keys[key] You will run into false positives for any property set on Object.prototype such as "toString" or "valueOf" (for instance consider {valueOf: 1}). keys[key] is not a sufficent as it will miss any falsey value (NaN, null, false, 0, "", etc). You should use either the in operation or hasOwnProperty