2017-01-19-binding-objects-to-functions.md

layout	title	tip-number	tip-username	tip-username-profile	tip-tldr	redirect_from	categories
post	Binding objects to functions	61	loverajoel	https://github.com/loverajoel	Understanding how to use `Bind` method with objects and functions in JavaScript	/en/binding-objects-to-functions/	en javascript

More than often, we need to bind an object to a function’s this object. JS uses the bind method when this is specified explicitly and we need to invoke desired method.

Bind syntax

fun.bind(thisArg[, arg1[, arg2[, ...]]])

Parameters

thisArg

this parameter value to be passed to target function while calling the bound function.

arg1, arg2, ...

Prepended arguments to be passed to the bound function while invoking the target function.

Return value

A copy of the given function along with the specified this value and initial arguments.

Bind method in action in JS

const myCar = {
 brand: 'Ford',
 type: 'Sedan',
 color: 'Red'
};

const getBrand = function () {
 console.log(this.brand);
};

const getType = function () {
 console.log(this.type);
};

const getColor = function () {
 console.log(this.color);
};

getBrand(); // object not bind,undefined

getBrand(myCar); // object not bind,undefined

getType.bind(myCar)(); // Sedan

let boundGetColor = getColor.bind(myCar);
boundGetColor(); // Red