[johny-kalesonny]

undefined

#javascript #nieprogramowanie

[p.....x]

if (typeof x === 'undefined' || x === null)

postujcie najlepsze

[PIENSCI_WONSZA]

typeof NaN -> "number"

[d.....n]

@johny-kalesonny: 2 + undefined = NaN
"2" + undefined = "2undefined"
new Boolean(new Boolean(false)).valueOf() = true
typeof new String("123") = object

Wszystko ma swoje uzasadnienie ( ͡° ͜ʖ ͡°)

[Marmite]

@johny-kalesonny: if (x !== x) { //x is NaN