Lodash _.findLastIndex() Function
Lodash _.findLastIndex() function is used to find the element from the right of the array. Therefore giving the index of the last occurrence of the element in the array.
Syntax:
findLastIndex(array, [predicate=_.identity], fromIndex);
Parameters:
- array: It is the original array.
- predicate: It is the function that iterates over each element.
- fromIndex: It is the index after which the search starts. If from Index is not given then by default it is n-1 where n is the length of the array.
Return Value:
It returns the index of the element if found else -1 is returned.
Example 1: In this example, we are getting the last index of element 2 that is present in the given array by the use of the lodash _.findLastIndex() function.
javascript
// Requiring the lodash library const _ = require( "lodash" ); // Original array let array1 = [4, 2, 3, 1, 4, 2] // Using lodash.findLastIndex let index = _.findLastIndex(array1, (e) => { return e == 2; }); // Original Array console.log( "original Array: " , array1) // Printing the index console.log( "index: " , index) |
Output:
Example 2: In this example, we are using the lodash _.findLastIndex() functionand getting “-1” as the element 1 is not present in the given array.
javascript
// Requiring the lodash library const _ = require( "lodash" ); // Original array let array1 = [4, 2, 3, 1, 4, 2] // Using lodash.findLastIndex let index = _.findLastIndex(array1, (e) => { return e == 1; }, 2); // Original Array console.log( "original Array: " , array1) // Printing the index console.log( "index: " , index) |
Output:
Example 3: In this example, we are getting the last index of element 2 that is present in the given array of objects by the use of the lodash _.findLastIndex() function.
javascript
// Requiring the lodash library const _ = require( "lodash" ); // Original array let array1 = [ { "a" : 1, "b" : 2 }, { "b" : 4 }, { "a" : 1 } ] // Using lodash.findLastIndex let index = _.findLastIndex(array1, (e) => { return e.b == 2; }, 2); // Original Array console.log( "original Array: " , array1) // Printing the index console.log( "index: " , index) |
Output: