Underscore.js _.binary() Method

The Underscore.js _.binary() method returns a new function that accepts only two arguments and passes these arguments to the given function. Additional arguments are discarded.

Syntax:

_.binary( fun )

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

• fun: This is the given function.

Return Value: It returns a new function.

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

npm install underscore-contrib

Example 1: 

Javascript

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

// Function
function fun(){
    var mul = 1;
     for (var i = 0; i < arguments.length; i++) {
         mul = mul * arguments[i];
     }
     return mul;
}

var gfgFunc = _.binary(fun);

console.log("Multiplication is :",
        gfgFunc(2,3));

Output:

Multiplication is : 6

Example 2:

Javascript

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

// Function
function fun() {
    var mul = 1;
     for (var i = 0; i < arguments.length; i++) {
         mul = mul * arguments[i];
     }
     return mul;
}

var gfgFunc = _.binary(fun);

// Only operates for first two parameters
console.log("Multiplication is :",
        gfgFunc(2,23,2,2));

Output: 

Multiplication is : 46

Example 3:

Javascript

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

// Function
function fun() {
    return arguments;
}

var gfgFunc = _.binary(fun);

// Only first two parameters will
// be used as arguments
console.log("Binary Arguments are :",
    gfgFunc("a", "b", "c", "d", "e"));

Output: 

Binary Arguments are : [Arguments] { '0': 'a', '1': 'b' }