Using typeof vs === to check undeclared variable produces different result

Question

If I have an undeclared variable and use typeof it tells me it\'s undefined. But if I then check it using if (qweasdasd === undefined)

Answer 1

You have an undefined variable, but not an undefined object value.

console.log(variable) // undefined
console.log(typeof variable) // "undefined"
console.log(variable === undefined) // Reference error
variable = undefined ; 
console.log(variable === undefined) // true