A JavaScript key-value array is a data structure that allows you to store an ordered collection of key-value pairs.


In an object-oriented programming paradigm, key-value arrays are a convenient way to manage objects. This makes it easy to add, modify, and delete key-value pairs.

With its intuitive syntax, JavaScript key-value array allows developers to access values by using keys, making it a reliable and flexible tool.

This type of array can be useful in various programming scenarios. Such as storing and retrieving data from a database. Or managing configuration settings in an application.

In JavaScript, you can create an array of key-value pairs using an object literal syntax or the Map constructor.

Here are examples of both:

1. Using object literal syntax

In this example, keyValueArray is an array containing three objects, each with a key and value property.

const keyValueArray = [
  { key: 'foo', value: 42 },
  { key: 'bar', value: 'hello world' },
  { key: 'baz', value: true }

How to access JavaScript key-value pair in an array of object literal syntax?

There are two ways to access key-value pair in an array of object literal syntax-

Using dot notation

const myObj = { foo: 42, bar: 'hello world' };
const fooValue = myObj.foo; // returns 42
const barValue = myObj.bar; // returns 'hello world'

Using bracket notation

const myObj = { foo: 42, bar: 'hello world' };
const fooValue = myObj['foo']; // returns 42
const barValue = myObj['bar']; // returns 'hello world'

2. Using the Map constructor

const keyValueMap = new Map([
  ['foo', 42],
  ['bar', 'hello world'],
  ['baz', true]

In this example, keyValueMap is a Map object containing three key-value pairs.

How to access JavaScript key-value pair in a Map constructor?

You can access the values by calling get() method of the Map object and passing the key as an argument, like this:

keyValueMap.get('foo'); // returns 42
keyValueMap.get('bar'); // returns 'hello world'
keyValueMap.get('baz'); // returns true

The get() method returns the value associated with that key, or undefined if the key is not found in the Map object.

Note that you can also use the has() method to check whether a particular key exists in the Map object before calling the get() method to avoid errors.


When used properly, a key-value array can help improve the efficiency and performance of your JavaScript code.

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