JavaScript - how to clear object

In this article, we would like to show you how to clear an object in JavaScript.

The below examples show solutions that:

1. assign new empty object ({}),
2. delete the object's properties.

Solution 1

In this solution, we create a new memory location with an empty object ({}) and we point existing object to that location.

Runnable solution:

// ONLINE-RUNNER:browser;

let user = {
    id: 1,
    name: 'John',
    age: 43
};

user = {};  // empty object operation

console.log(JSON.stringify(user, null, 4));  // {}

Notes:

• in that approach, the object cannot be const,
• that approach changes variable reference.

Solution 2

In this section, we use for loop to iterate over object properties and delete them.

Note: that approaches are slow when we empty large objects.

2.1. for..in loop solution 

Runnable solution:

// ONLINE-RUNNER:browser;

const emptyObject = (object) => {
    for (const name in object) {
        if (object.hasOwnProperty(name)) {
            delete object[name];
        }
    }
};


// Usage example:

const user = {
    id: 1,
    name: 'John',
    age: 43
};

emptyObject(user);  // empty object operation

console.log(JSON.stringify(user, null, 4));  // {}

2.2. Object.keys() method solution

Runnable solution:

// ONLINE-RUNNER:browser;

const emptyObject = (object) => {
    const keys = Object.keys(object);
    for (const key of keys) {
        delete object[key];
    }
};


// Usage example:

const user = {
    id: 1,
    name: 'John',
    age: 43
};

emptyObject(user);  // empty object operation

console.log(JSON.stringify(user, null, 4));  // {}