find index of element in list javascript 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: how to find the index of a value in an array in javascript

var list = ["apple","banana","orange"]

var index_of_apple = list.indexOf("apple") // 0

Example 3: js find index in list

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

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

Example 4: findindex js

// 	findIndex(callback fn)  

//	.... return index (when condition meets)
//  .... return -1 (if condition not meets)

const array = [5, 12, 8, 130, 44];

/// it returns the index of number which satisfy the condition true
const index = array.findIndex((item)=> item>10);   //1

/// now we can check what element at that index...
console.log(array[index]); // array[1]

Example 5: js get index of item in array

array.indexOf("item");

Example 6: get index of element in array javascript

var scores = [10, 20, 30, 10, 40, 20];
console.log(scores.indexOf(30)); // 2
console.log(scores.indexOf(50)); // -1