𝐁𝐢𝐧𝐝, 𝐂𝐚𝐥𝐥, 𝐚𝐧𝐝 𝐀𝐩𝐩𝐥𝐲 𝐌𝐞𝐭𝐡𝐨𝐝𝐬 𝐢𝐧 𝐉𝐚𝐯𝐚𝐒𝐜𝐫𝐢𝐩𝐭

#javascript #beginners #programming #webdev

𝗕𝗶𝗻𝗱
The bind method creates a new function and sets ‘this’ keyword to the specified object.

𝑬𝒙𝒂𝒎𝒑𝒍𝒆:
const showNum= {
num: 50,
getNum: function() {
return this.num;
}
};

const unboundGetNum = showNum.getNum;
console.log(unboundGetNum());
// The function gets invoked at the global scope
// expected output: undefined

const boundGetNum= unboundGetNum.𝗯𝗶𝗻𝗱(showNum);
console.log(boundGetNum());
// expected output: 50

𝐂𝐚𝐥𝐥
The call method sets “this” inside the function and immediately executes that function. Call() accepts 𝘤𝘰𝘮𝘮𝘢-𝘴𝘦𝘱𝘢𝘳𝘢𝘵𝘦𝘥 list of arguments.

𝑬𝒙𝒂𝒎𝒑𝒍𝒆:
function Gadget(name, price) {
this.name = name;
this.price = price;
}
function Laptop(name, price) {
Gadget.𝗰𝗮𝗹𝗹(this, name, price);
this.category = 'laptop';
}
console.log(new Laptop('Asus', 5).name);
// expected output: "Asus"

𝗔𝗽𝗽𝗹𝘆
The apply() method is similar to call(). The difference is that the apply() method accepts an 𝑎𝑟𝑟𝑎𝑦 𝑜𝑓 𝑎𝑟𝑔𝑢𝑚𝑒𝑛𝑡𝑠 instead of comma separated values.

𝑬𝒙𝒂𝒎𝒑𝒍𝒆:
const person = {
firstName: 'Jahid',
lastName: 'Iqbal'
}
function greet(greeting, message) {
return ${greeting} ${this.firstName} ${this.lastName}. ${message};
}
let result =greet.𝗮𝗽𝗽𝗹𝘆(person, ['Hello', 'How are you?']);

console.log(result);
// expected output: "Hello Jahid Iqbal. How are you?"