How to check that the map collection contains two identical elements?

Question

JavaScript

Hello everyone, can someone tell me how to check that the map collection contains two identical elements? For example, there is a collection map :

Map(4) {
'0' => { id: 1 },
'1' => { id: 2 },
'2' => { id: 3 },
'3' => { id: 1 }
}

How can I check that there are two identical emails in it. ? In this case, two objects with id : 1

Answer 1

Cycle.