lastIndexOf() – Last Index of Element
array.lastIndexOf(searchElement)
array.lastIndexOf(searchElement, fromIndex)
array
is an array of elements in which we need to find the index of specified elementlastIndexOf
is the array method namesearchElement
is the element to search for in the arrayfromIndex
is an integer, optional value. default value is 0
lastIndexOf()
method searches the searchElement
from the end of the array towards the start, and returns the index of the searchElement
when there is a match, or returns -1
if the searchElement
is not present in the array. if fromIndex
is passed as second argument to lastIndexOf()
, then the search for the element
starts at index fromIndex
from the end of the array
Examples
1. find the last index of the element 'cherry'
in the array fruits
let fruits = ['apple', 'banana', 'cherry', 'mango', 'banana'];
let searchElement = 'banana';
let lastIndex = fruits.lastIndexOf(searchElement);
if ( lastIndex != -1 ) {
console.log(`last index of ${searchElement} in array is ${lastIndex}`);
} else {
console.log('element is not present in array');
}
2. find the last index of the element 'guava'
in the array fruits
, given that the element is not present in the array
let fruits = ['apple', 'banana', 'cherry', 'mango', 'banana'];
let searchElement = 'guava';
let lastIndex = fruits.lastIndexOf(searchElement);
if ( lastIndex != -1 ) {
console.log(`last index of ${searchElement} in array is ${lastIndex}`);
} else {
console.log('element is not present in array');
}
3. find the last index of the element 'banana'
in the array fruits
, after a fromIndex
of 2
let fruits = ['apple', 'banana', 'cherry', 'mango', 'banana'];
let searchElement = 'banana';
let lastIndex = fruits.lastIndexOf(searchElement, 2);
if ( lastIndex != -1 ) {
console.log(`last index of ${searchElement} in array is ${lastIndex}`);
} else {
console.log('element is not present in array');
}