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Object.entries() Method – Copy an Object's Key-Value Pairs into an Array

Whenever you use Object.entries() on a JavaScript object, the method does the following:

  • It creates a new array.
  • It copies the specified object's enumerable own key-value pairs into the newly created array.
  • It returns the new array containing one or more nested arrays. Each nested array has two items: the property's key (always represented as a string item) and the property's value.

Syntax of the Object.entries() Method

Object.entries() accepts a single argument. Here's the syntax:

Object.entries(objectArgument);

The objectArgument refers to the JavaScript object whose key-value pairs you want to extract into a new array.

note

The Object.entries() method does not alter the original object.

Examples of the Object.entries() Method

Below are examples of the Object.entries() method.

Copy an object's key-value pairs into a new array

const profile = {
firstName: "Oluwatobi",
lastName: "Sofela",
companyName: "CodeSweetly",
npmPackage: "@codesweetly/react-youtube-playlist",
id: 9103,
};

const formData = Object.entries(profile);

console.log(formData);

// The invocation above will return:
// [
// ["firstName", "Oluwatobi"],
// ["lastName", "Sofela"],
// ["companyName", "CodeSweetly"],
// ["npmPackage", "@codesweetly/react-youtube-playlist"],
// ["id", 9103],
// ]

Try Editing It

Copy an array's key-value pairs into a new array

const myBio = ["Oluwatobi", "Sofela", "CodeSweetly", 9103];

const itemsInMyBio = Object.entries(myBio);

console.log(itemsInMyBio);

// The invocation above will return:
// [
// ["0", "Oluwatobi"],
// ["1", "Sofela"],
// ["2", "CodeSweetly"],
// ["3", 9103],
// ]

Try Editing It

Copy a string's key-value pairs into a new array

const firstName = "Oluwatobi";

const itemsInFirstName = Object.entries(firstName);

console.log(itemsInFirstName);

// The invocation above will return:
// [
// ["0", "O"],
// ["1", "l"],
// ["2", "u"],
// ["3", "w"],
// ["4", "a"],
// ["5", "t"],
// ["6", "o"],
// ["7", "b"],
// ["8", "i"],
// ]

Try Editing It

The Object.entries() method successfully extracted the string's key-value pairs because strings are the only primitive data with enumerable own properties.

tip

Overview

This article discussed what the Object.entries() method is. We also used examples to see how it works.

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