javascript - How to see if an array has 2 or more elements that are the same?

Question

This question already has answers here: question from:https://stackoverflow.com/questions/65927471/how-to-see-if-an-array-has-2-or-more-elements-that-are-the-same

Answer 1

A simple way is to use a Set.

function doesContainDups(array) {
   let set = new Set(array);
   return set.size !== array.length;
}

console.log(doesContainDups(["item1", "item2", "item3"]));
console.log(doesContainDups(["item1", "item2", "item1"]));