As far as I know, not using var will put any declaration in the global scope. So while you wouldn't want to do that on a real production app. Using it for these little solutions isn't necessarily wrong. As you probably don't need to worry about your namespace

here's an example:
drink = 'beer'
function drunk () {
console.log(drink)
}
drunk()
//'beer'
function wino () {
var drink = 'wine';
console.log(drink)
}
wino()
// 'wine'
drink
// 'beer'

ths Zozo. too noob to understand the quiz T^T

take While means you take items while condition is true.
So :

takeWhile([ 1, 4, 2, 3, 5, 4, 5, 6, 7 ], isEven ) // -> [] because 1 is not even
takeWhile([ 2, 100, 1000, 10000, 5, 3, 4, 6 ], isEven ) // ->  [2,100,1000,10000] because 5 (after 10000) is not even
... and so on...

think issue should be marked solved