Answers for "how to check index in javascript"

javascript indexOf object value in array

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

get index of element in array js

const beasts = ['ant', 'bison', 'camel', 'duck', 'bison'];

beasts.indexOf('bison'); //ouput: 1

// start from index 2
beasts.indexOf('bison', 2); //output: 4

beasts.indexOf('giraffe'); //output: -1