Question

What's the value of output?

const one = false || {} || null;
const two = null || false || '';
const three = [] || 0 || true;

console.log(one, two, three);

• A: false null []
• B: null "" true
• C: {} "" []
• D: null null true

Answer 1

Answer: C

With the || operator, we can return the first truthy operand. If all values are falsy, the last operand gets returned.

(false || {} || null): the empty object {} is a truthy value. This is the first (and only) truthy value, which gets returned. one is equal to {}.

(null || false || ""): all operands are falsy values. This means that the last operand, "" gets returned. two is equal to "".

([] || 0 || ""): the empty array[] is a truthy value. This is the first truthy value, which gets returned. three is equal to [].