How to get an array's index which object has a certain property value.

findIndex.js

let items = [
  {"id": "aaa"},
  {"id": "bbb"},
  {"id": "ccc"},
  {"id": "bbb"},
];

let idx;
idx = items.findIndex(x => x.id == "aaa"); // idx => 0
idx = items.findIndex(x => x.id == "bbb"); // idx => 1 // returns idx of "bbb" first found
idx = items.findIndex(x => x.id == "ccc"); // idx => 2
idx = items.findIndex(x => x.id == "xxx"); // idx => -1 // returns -1 if not found