# String in JS

In JavaScript, a string is a sequence of characters enclosed in single or double quotes. For example:

```javascript
let name = "John Doe";
let message = 'Hello World!';
```

Strings have several built-in methods that can be used to manipulate and retrieve information from strings. Some examples include:

## 1\. `.length`:

This property returns the length of a string.

```javascript
let name = "John Doe";
console.log(name.length); // Output: 8
```

## 2\. `.concat()`:

This method concatenates (joins) two or more strings and returns a new string.

```javascript
let firstName = "John";
let lastName = "Doe";
let fullName = firstName.concat(" ", lastName);
console.log(fullName); // Output: "John Doe"
```

## 3\. `.toUpperCase()`:

This method converts all the characters in a string to uppercase.

```javascript
let message = 'Hello World!';
console.log(message.toUpperCase()); // Output: "HELLO WORLD!"
```

## 4\. `.toLowerCase()`:

This method converts all the characters in a string to lowercase.

```javascript
let message = 'Hello World!';
console.log(message.toLowerCase()); // Output: "hello world!"
```

## 5\. `.indexOf()`:

This method returns the index of the first occurrence of a specified string value.

```javascript
let message = 'Hello World!';
console.log(message.indexOf("World")); // Output: 6
```

## 6\. `.slice()`:

This method extracts a part of a string and returns a new string.

```javascript
let message = 'Hello World!';
console.log(message.slice(7)); // Output: "World!"
```

## 7\. `.split()`:

This method splits a string into an array of substrings.

```javascript
let message = 'Hello World!';
console.log(message.split(" ")); // Output: ["Hello", "World!"]
```

## 8\. `.replace()`:

This method replaces a specified value with another value in a string.

```javascript
let message = 'Hello World!';
console.log(message.replace("World", "Friend")); // Output: "Hello Friend!"
```

## 9\. `.trim()`:

This method removes whitespace from both ends of a string.

```javascript
let message = '   Hello World!   ';
console.log(message.trim()); // Output: "Hello World!"
```

These are just a few examples of the built-in methods available for strings in JavaScript. Knowing how to use these methods can make it much easier to manipulate and work with strings in your code.