Array.size() vs Array.length

Question

What is the difference between the two?

So I know that array.size() is a function while array.length is a property. Is there a usecase for

Answer 1

Size detects duplicates, it will return the number of unique values

const set1 = new Set([1, 2, 3, 4, 5, 5, 5, 6]);
console.log(set1.size);
// expected output: 6