Determine index of a JS object in array while knowing the object value

Question

How do I determine what the index of an object is within an array?

Take the following setup:

var item = [
 {
 identifier: "id1",
 },
 {
 identifier: "id2",
 },
 {
 identifier: "id3",
 }
];

I know what the object value is and that it exists and currrently have it stored like this currentValue = "id2";

What i'd like to know is that "id2" equals to (in this case) index 1.

Answer 1

The only way is to iterate and check each property

var currentValue = "id2";
var item = [
 {
 identifier: "id1",
 },
 {
 identifier: "id2",
 },
 {
 identifier: "id3",
 }
];
var index = 0;
item.forEach(function(obj, i) {
 if ( obj.identifier === currentValue ) {
 index = i;
 return false;
 }
});
document.body.innerHTML = index;