how to get index number of array of object in javascript code example

Example 1: javascript get index of object with value in array

// Get index of object with specific value in array
const needle = 3;
const haystack = [{ id: 1 }, { id: 2 }, { id: 3 }];
const index = haystack.findIndex(item => item.id === needle);

Example 2: js find index in list

let myList = ['foo', 'bar', 'qux'];

myList.indexOf('bar');	// 1