Array Or Object In JavaScript language.
Tags: javascript, beginners, tutorial, git
Published: 2022-12-23 09:12:39



![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/immce2131hmns1zpi44i.jpg)

**Array** or **Object** It is a very important topic in JS.
If you want to learn javaScript in a website, youTube, book or All facilities.. there is a subject with this name => **Array** and **object**.
And something else that should be here, is difference between these two => Array and Object.
in first we should know what is Array! and then what is Object!!


before I explain, I want to tell you some resources for learn JS.

1. https://www.w3schools.com/js/default.asp

2. https://overapi.com/javascript

3.https://www.javascript.com/



but you should know "Books" is better than every choice for learn JS.

> 
like "**javasSript from beginner to professional**" || "**you don't know javaScript**"

( yup, I use || for Or;) if you know..).

## syntax of a Array:

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/rnlzv331x9jolfmeivvz.PNG)

> There are three points here:
1. I use `[]` for write a **Array**.
2. I use any name I like for **Variable**.
3. I can use from **var** or **let** instead **const**.(but there is some rules for that, and usually we use **const** for write a Array.)

> if you don't know what is **var** or **let** or maybe **const**, check here:

> https://www.w3schools.com/js/js_variables.asp

## syntax of Object:

![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/kieh12lthlm1ziqvapvh.PNG)

> and Object Points..:
1. I use`{}` for write a Object.
2. I use a **variable** for every item in Object.
3. name, age, nationality its a "key" for "value" I wrote in front of it.

> well, in end remember that: 
> name, age, etc.. its a "key" 
> ana, 19, etc.. its a "value"
> and we say that => 
> **name** is a **key** for **ana** and **ana** its a **value**.
=> We say in the term (key-value).

## syntax for **array**:

```
const arrayName = [value1, value2,...]
```

## syntax for **object**:

```
const objectName = {key1 : value1, ...}
```

## The difference between Array And Object:

now we should let's answer to that question:
what is difference between a Array and a object?

as you can see: I wrote **array** with [ ] and then I wrote directly value on it.

and then I wrote **object** with { } and write value but after key of that value.

but the main difference between a **Array** and **Object** its **index** of these two.

"index" its really easy and important subject and rule for array and object in JS.

in a Array every value from first have a index and that index start with 0, and then 1 and then 2 and...n. you should know we can't change that rule for Array. but in object:

in a Object every value from first have index but that index is what we call, for example for "ana" I give "name" for index of this value.
for another value I give index I want, after that in our program we wrote and we have Object
every value in Object have index and that index its "key" we wrote for value.
 

## summery:

> index of **array** start with 0,1,2,...:

```
const array1 = ["a", "b"]
```
=> index of "a" its: 0
=> index of "b" its: 1

> index of **object** start with key1, key2,..:

```
const object1 = {name: "ana", age:"19"}
```
=> index of "ana" its name
=> index of "19" its age

_forgive me if I forget **semicolon** :)_

The end.