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// Example code explaining data types in JavaScript

// Number type
let age;
let height = 170.5;

// String type
let name = 'John';
let message = 'Hello, how are you?';

// Boolean type
let isStudent = true;
let hasDriverLicense = false;

// Object type
let student = {
  name: 'John',
  age: 16,
  grade: '10th grade',
};

// Array type
let fruits = ['Apple', 'Banana', 'Grape'];

// Checking data types
console.log(`The type of age: ${typeof age}`); // number

console.log(`The type of height: ${typeof height}`); // number

console.log(`The type of name: ${typeof name}`); // string

console.log(`The type of message: ${typeof message}`); // string

console.log(`The type of isStudent: ${typeof isStudent}`); // boolean

console.log(`The type of hasDriverLicense: ${typeof hasDriverLicense}`); // boolean

console.log(`The type of student: ${typeof student}`); // object

console.log(`The type of fruits: ${typeof fruits}`); // object

# What is a Data Type?

A data type refers to the `type` of data such as text, numbers, and boolean values.

 

## 1. Number

Represents numeric values like integers, floats, and natural numbers.

Example:

```javascript title="Number Data Type"
let age = 16;
let height = 170.5;
```

 

## 2. String

A string represents text information. It includes letters, words, or sentences enclosed in quotes (' ', " ").

Example:

```javascript title="String Data Type"
let name = 'John';
let message = 'Hello!';
```

 

## 3. Boolean

The Boolean data type can have one of two values: `true` or `false`, similar to a switch being toggled on or off.

Example:

```javascript title="Boolean Data Type"
let isStudent = true;
let hasDriverLicense = false;
```

 

## 4. Object

An object is a data type used to store collections of data. For example, a student object may contain the student's name, age, and grade.

Example:

```javascript title="Object Data Type"
let student = {
 name: 'John',
 age: 16,
 grade: 'Sophomore',
};
```

 

## 5. Array

An array is a list of values of the same type.

```javascript title="Array Data Type"
let fruits = ['Apple', 'Banana', 'Grapes'];
```

 

## 6. Other Data Types

- `null`

`null` is a special value that represents 'no value'. It is used to explicitly signify that a variable has no value assigned.

Example:

```javascript title="null Data Type"
let emptyValue = null;
```

 

- `undefined`

`undefined` is a value assigned to variables that have been declared but not yet assigned a value. It indicates that a variable has not been defined with a value. If you declare a variable and do not initialize it, JavaScript automatically assigns it the value `undefined`.

Example:

```javascript title="undefined Data Type"
let notDefinedYet;
console.log(notDefinedYet); // Output: undefined
```

- Both `null` and `undefined` signify the absence of value, but they are used in different contexts and have different meanings. `null` is used to explicitly state the absence of a value, whereas `undefined` indicates that a variable has been declared but not yet assigned a value.

Data Types