JavaScript string methods
Published: 2021-12-28 13:27:34

Today I am telling you about the most important JavaScript string methods with explanations and examples.

**charAt():** This method is used for extracting string characters. This method returns the character at a  specific index in a string.

```
let text = "FEROJ ALAM";
let char = text.charAt(0); //output F
```

**concat():** This method is used to join two or more strings together.

```
let text1 = "Feroj";
let text2 = "Alam";
let text3 = text1.concat(" ", text2); //output Hello World
```
concat() can be used instead of plus operator.

```
text = "Feroj" + " " + "Alam";  //output Feroj Alam
text = "Hello".concat(" ", "World!");  //output Hello World
```
These two line are same

**includes():** This method is used to check that string we are searching for exists in that string. If string exists then it will return true, if not exist return false.

```
let text = "Feroj Alam, web developer.";
let result = text.includes("web"); // true
```
includes() method is case sensitive.

**endsWith():** This method is used to check that string ends with the string that we are searching for. If exists it will return true otherwise return false. This method is case-sensitive.

```
let text = "Programming Hero";
let result = text.endsWith("Hero");//output true
let text = "Programming Hero";
let result = text.endsWith("hero");//output false
```

**indexOf():** This method is used to find the position of a string. This method returns the first found string that we are looking for. If not found it returns -1. This method is also case-sensitive.

```
let text = "Hello world, welcome to the universe.";
let result = text.indexOf("welcome"); // output 13
let text = "Hello world, welcome to the universe.";
let result = text.indexOf("Welcome"); // output -1
```
**lastIndexOf():** This method is used to find the last positioned string position. It starts to find the string from the last. It gives the index from starting 0. It returns -1 if the value is not found. This method is case-sensitive.

```
let text = "Hello planet earth, you are a great planet.";
let result = text.lastIndexOf("planet"); //output 36
let text = "Hello planet earth, you are a great planet.";
let result = text.lastIndexOf("Planet"); //output -1
```
 
**replace():** This method is used to replace string for a given value or a regular expression. It returns a new string with replaced value. It does not change the original string.

```
let text = "Visit Microsoft!";
let result = text.replace("Microsoft", "Google"); //output Visit Google
let text = "Mr Blue has a blue house and a blue car";
let result = text.replace(/blue/g, "red"); //output Mr Blue has a red house and a red car
```
 
**slice():** This method is used to extract specific strings. It returns the extracted string in a new string but does not change the original string. We have to give start and end index to slice or cut like (0, 5) and if we give a negative value it will extract from the last of string.

```
let text = "Hello world!";
let result = text.slice(0, 5);//output Hello
let result = text.slice(3);//output lo world!
```
 
**split():** This method is used to split or separate words to make an array. It will return a new array. It does not change the original string.

```
let text = "How are you doing today?";
const myArray = text.split(" "); //output How,are,you,doing,today?
const myArray = text.split(""); //output H,o,w, ,a,r,e, ,y,o,u, ,d,o,i,n,g, ,t,o,d,a,y,?
```
If we use (“ “) this as separator, string will split into words
 
**startsWith():** This method is used to check that the string starts with the string that we are searching for. If found it returns true otherwise returns false. This method is case-sensitive.

```
let text = "Hello world, welcome to the universe.";
text.startsWith("Hello"); //output true
```
 
**substr():** It is used to extract or cut a part of a string.it receives the start and end position of extraction.it does not change the original string.
 

```
let text = "Hello world!";
let result = text.substr(1, 4); //output ello
let result = text.substr(2); //output llo world!
```
 
**toLowerCase():** This method is used convert lowercase the characters of a string. It does not change the original string.

```
let text = "Hello World!";
let result = text.toLowerCase(); //output hello world!
```
 
**toUpperCase():** It is used to convert the characters of a string to upper case. It also does not change the original string.

```
let text = "Hello World!";
let result = text.toUpperCase(); //HELLO WORLD!
```
 
**trim():** This method is used to remove extra spaces from both sides of a string. It does not change the original string.

```
let text = "   	Hello World!    	";
let result = text.trim();//output Hello World!
```
 
**trimStart():** This method is used to remove white space from the beginning of a string. If there is no white space it will return a new string without throwing an error.

```
let text = "   	    Hello World!";
let result = text.trimStart();//output Hello World!
```
 
**trimEnd():** It is used to remove white space from the ending of a string.If there is no white space it will return a new string without throwing an error.

```
let text = "Hello World!          ";
let result = text.trimEnd();//output Hello World!
```