Lodash _.comparator() Method

The Lodash _.comparator() method takes a binary predicate-like function and returns a comparator function which can be used as a callback for _.sort() method etc.

Syntax:

_.comparator( function );

Parameters: This method accepts a single parameter as listed above and discussed below.

• function: It is a predicate like defined function.

Return Value: This method returns a comparator function.

Note: To execute the below examples, you have to install the lodash-contrib library by using this command prompt and execute the following command.

npm install lodash-contrib

Below examples illustrate the Lodash _.comparator() method in JavaScript:

Example 1: Sorting using a comparator function.

Javascript

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

var gfgFun = function(x, y) {
    // Returns -1, 0 or 1
    return x <= y;
};

// Array
var arr = [4, 8, 2, 9, 1];

var comp = _.comparator(gfgFun);
// Using comparator function with _.sort() method
arr.sort(comp);

console.log("Sorted Array :",arr)

Output:

Sorted Array : [ 1, 2, 4, 8, 9 ]

Example 2: Reverse Sorting using a comparator function.

Javascript

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

var gfgFun = function(x, y) {
    // Returns -1, 0 or 1
    return x >= y;
};

// Array
var arr = [1, 10, 2, 9, 1];

var comp = _.comparator(gfgFun);
// Using comparator function with _.sort() method
arr.sort(comp);

console.log("Sorted Array :",arr)

Output:

Sorted Array : [ 10, 9, 2, 1, 1 ]