Interview question

How does Object.create() work and how is it different from using 'new'? Object.create() कैसे काम करता है और 'new' से कैसे अलग है?

Answer

Object.create() creates a new object with a specified prototype directly, without invoking a constructor function - giving explicit control over the prototype link.

// Object.create with an explicit prototype object
const animal = {
    eats: true,
    walk() {
        console.log(`${this.name} is walking`);
    }
};

const rabbit = Object.create(animal);
rabbit.name = 'Rabbit';
rabbit.jumps = true;

console.log(rabbit.eats);   // true - inherited
rabbit.walk();               // Rabbit is walking
console.log(Object.getPrototypeOf(rabbit) === animal); // true

// Object.create(null) - object with NO prototype at all (not even Object.prototype)
const pureDict = Object.create(null);
pureDict.key = 'value';
console.log(pureDict.toString); // undefined - no inherited methods at all
// Useful for objects used purely as dictionaries/maps, avoiding prototype pollution

// Object.create with property descriptors (second argument)
const obj = Object.create(animal, {
    name: { value: 'Bunny', writable: true, enumerable: true }
});
console.log(obj.name); // Bunny

// Comparison: using 'new' with a constructor function
function Animal(name) {
    this.name = name;
}
Animal.prototype.eats = true;

const newAnimal = new Animal('Cat');
// 'new' does 4 things: 1) creates a new object, 2) sets its prototype to
// Animal.prototype, 3) calls Animal with 'this' bound to the new object,
// 4) returns the new object (unless the constructor returns its own object)

// Object.create is more direct - no constructor function/logic needed,
// just specify the prototype object explicitly

Object.create() specified prototype के साथ सीधे नया object बनाता है, constructor function invoke किए बिना - prototype link पर explicit control देता है।

const animal = {
    eats: true,
    walk() {
        console.log(`${this.name} is walking`);
    }
};

const rabbit = Object.create(animal);
rabbit.name = 'Rabbit';
rabbit.jumps = true;

console.log(rabbit.eats);   // true - inherited
rabbit.walk();               // Rabbit is walking
console.log(Object.getPrototypeOf(rabbit) === animal); // true

// Object.create(null) - बिल्कुल prototype नहीं
const pureDict = Object.create(null);
pureDict.key = 'value';
console.log(pureDict.toString); // undefined - कोई inherited methods नहीं

// Property descriptors के साथ
const obj = Object.create(animal, {
    name: { value: 'Bunny', writable: true, enumerable: true }
});
console.log(obj.name); // Bunny

// 'new' के साथ compare करना
function Animal(name) {
    this.name = name;
}
Animal.prototype.eats = true;

const newAnimal = new Animal('Cat');
// 'new' चार काम करता है: 1) नया object बनाना, 2) prototype set करना,
// 3) constructor को call करना 'this' bind करके, 4) object return करना

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