javascript find return index code example

Example 1: react array find index

//The findIndex() method returns the index of the first element 
//in the array that satisfies the provided testing function.
//Otherwise, it returns -1, indicating that no element passed the test.
const array1 = [5, 12, 8, 130, 44];

const isLargeNumber = (element) => element > 13;

console.log(array1.findIndex(isLargeNumber));
// expected output: 3

Example 2: js find index in list

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

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

Example 3: get index of element in array js

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

console.log(beasts.indexOf('bison'));
// expected output: 1

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

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

//*** Thanks to MDN Web Docs ***//
//https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Objets_globaux/Array/indexOf

Example 4: js get index of item in array

array.indexOf("item");

Example 5: get the index of object in array

var elementPos = array.map(function(x) {return x.id; }).indexOf(idYourAreLookingFor);
var objectFound = array[elementPos];