isPrototypeOf js
/"Checks if an object exists in another object's prototype chain."/
function Bird(name) {
this.name = name;
}
let duck = new Bird("Donald");
Bird.prototype.isPrototypeOf(duck);
// returns true
3
2
const user = { name: 'John' };
const arr = [ 1, 2, 3 ];
console.log('Original state');
console.log(user); // { name: 'John' }
console.log(user[1]); // undefined
console.log(user.__proto__); // {}
console.log(user.length); // undefined
Object.setPrototypeOf(user, arr); // добавляем прототип arr к user
console.log('Modified state');
console.log(user); // Array { name: 'John' }
console.log(user[1]); // 2
console.log(user.__proto__); // [ 1, 2, 3 ]
console.log(user.length); // 3
Thank you!
2
0
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