Object Methods

Object.assign() #

The Object.assign() method is used to copy properties from one or more enumerable source objects to a target object.
It returns the target object.

Parameters:

target The target object.

Return value

The target object.

const target = {a : 1, b : 2};
const source = {b : 4, c : 5};

const returnedTarget = Object.assign(target, source);

console.log(target);
// { a : 1  , b : 4 , c : 5 }

console.log(returnedTarget);
// { a : 1  , b : 4 , c : 5 }

target and returnedTarget are the same data.

Even if objects look the same, their data can be different.

keys() #

keys() extracts the object's keys and turns them into an array.

const user ={
 name : "huemang",
 age : 17,
 email: "s22043@gsm.hs.kr"
}

const keys = Object.Keys(user);
console.log(keys);
// ['name' , 'age' , 'email']

console.log(user['email']);

const values = keys.map(key => user[key]);
console.log(values);
// ['huemang' , 17 , 's22043@gsm.hs.kr ]

The indexing method using square brackets was used for object data. Let's learn more about it later.