What do indexOf, includes, every, and some return in these edge cases?

const values = [1, NaN, 3];
console.log(values.indexOf(NaN));
console.log(values.includes(NaN));
console.log(values.findIndex(Number.isNaN));
 
const empty = [];
console.log(empty.every((n) => n > 100));
console.log(empty.some((n) => n > 100));
console.log(empty.find((n) => n > 100));