Falsy Bouncer - reference error for isNan

Tell us what’s happening:

Keep getting a reference error for the global function ‘isNan’. Also tried Number.isNan() - same error. Does anyone know why?

Your code so far

function bouncer(arr) {
  arr = arr .filter( removeFalse );
  return arr;
}

function removeFalse(a) {
return a!=false && a!=null && a!=0 && a!="" && a!==undefined && !isNan(a);
}

bouncer([7, "ate", "", false, 9]);

Your browser information:

Your Browser User Agent is: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0.

Link to the challenge:
https://www.freecodecamp.org/challenges/falsy-bouncer

Turns out it should be isNaN, thanks for the tip.