Lodash _.bindKey() Method

Lodash _.bindKey() method of Function in lodash is used to create a function that calls the method at the object[key] along with the partials added to the arguments it accepts.

Note:

• This method is different from the _.bind() method as it permits bound functions to mention methods that may be reinterpreted or do not still exist.
• The _.bindKey.placeholder value that is by default ( _ ) in monolithic builds which is utilized as a placeholder for partially used arguments.

Syntax:

_.bindKey(object, key, partials);

Parameters:

• object: It is the object that is used to call the method.
• key: It is the key to be used in the method.
• partials: It is the arguments that are to be partially applied. It is an optional parameter.

Return Value:

• This method returns the new bound function.

Example 1: In this example, we are passing partials to the function and printing the result into the console by the use of the lodash _.bindKey() method.

// Requiring lodash library
const _ = require('lodash');

// Defining object parameter of this method
let obj = {
    'author': 'Nidhi',
    'welcome': function (greet, mark) {
        return greet + ' ' + this.author + mark;
    }
};

// Using the _.bindKey() method 
// with its parameters
let bound_fun =
    _.bindKey(obj, 'welcome', 'Hello');

// Calling bound_fun by passing its value
console.log(bound_fun('!!'));

Output:

Hello Nidhi!!

Example 2: In this example, we are passing partials to the function and using a bound with the placeholder then printing the result into the console by the use of the lodash _.bindKey() method.

// Requiring lodash library
const _ = require('lodash');

// Defining object parameter of this method
let obj = {
    'portal': function (portal, mark) {
        return 'Welcome to ' + portal + mark;
    }
};

// Using the _.bindKey() method with its
// parameters and a placeholder
let bound_fun =
    _.bindKey(obj, 'portal', _, '!');

// Calling bound_fun by passing its value
console.log(bound_fun('GeeksforGeeks'));

Output:

Welcome to GeeksforGeeks!