JavaScript Object.entries()

Summary: in this tutorial, you will learn how to use the JavaScript Object.entries() method.

Introduction to JavaScript Object.entries() method

ES2017 introduces the Object.entries() method that accepts an object and returns its own enumerable string-keyed property [key, value] pairs of the object.

Here is the syntax of the Object.entries() method:

Object.entries()Code language: JavaScript (javascript)

See the following example:

const ssn = Symbol('ssn');
const person = {
    firstName: 'John',
    lastName: 'Doe',
    age: 25,
    [ssn]: '123-345-789'
};

const kv = Object.entries(person);

console.log(kv);Code language: JavaScript (javascript)

Output:

[
    ['firstName', 'John'],
    ['lastName', 'Doe'],
    ['age', 25]
]Code language: JSON / JSON with Comments (json)

In this example:

• The firstName, lastName, and age are own enumerable string-keyed property of the person object, therefore, they are included in the result.
• The ssn is not a string-key property of the person object, so it is not included in the result.

Object.entries() vs. for…in

The main difference between the Object.entries() and the for...in loop is that the for...in loop also enumerates object properties in the prototype chain.