Underscore.js _.isIndexed() Method

The _.isIndexed() method checks whether the given value can be considered “Indexed” or not and returns the corresponding boolean value. Indexed value is one that accepts a numerical index to access its elements.

Syntax:

_.isIndexed( value );

Parameters:

• value: Given value to be checked for Indexed value.

Return Value: This method returns a Boolean value(Returns true if the given value is Indexed, else false).

Note: This will not work in normal JavaScript because it requires the underscore.js contrib library to be installed. Underscore.js contrib library can be installed using npm install underscore-contrib .

Example 1: An array can be considered as Indexed value and its elements can be accessed using numerical indexes.

Javascript

// Defining underscore contrib variable
var _ = require('underscore-contrib');

// Checking
console.log("The Value is Indexed : "
    + _.isIndexed([1, 3, 5]));

Output:

The Value is Indexed : true

Example 2: This method returns false for a mapping.

Javascript

// Defining underscore contrib variable
var _ = require('underscore-contrib');

// Checking
console.log("The Value is Indexed : "
    + _.isIndexed({1:3, 2:3}));

Output:

The Value is Indexed : false

Example 3: For a string, this method returns true.

Javascript

// Defining underscore contrib variable
var _ = require('underscore-contrib');

// Checking
console.log("The Value is Indexed : "
    + _.isIndexed("GeeksforGeeks"));

Output:

The Value is Indexed : true