### Length of a String
```javascript
let firstName = "Vaishali";
console.log(firstName.length);
```
### Access String Element
```javascript
console.log(firstName.charAt(2)); // i
console.log(firstName[2]); // i
console.log(firstName.charCodeAt(2)); // 115 (Ascii Code)
```
### Check Presence of Character
```javascript
console.log(firstName.includes("r")); // false (& if present it return true)
console.log(firstName.indexOf("i")); // 2 (& if not present it return -1)
console.log(firstName.lastIndexOf("i")); // 7
```
### Compare Two Strings
```javascript
let anotherName = "Vishal";
console.log(firstName.localeCompare(anotherName)); // -1 (& if strings are equal it return 0)
```
### Replace Substring
```javascript
const str = "Vishal is Best Frontend Developer. Vishal is Best Developer. ";
console.log(str.replace("Vishal", "Sujit")); // "Sujit is Best Frontend Developer. Vishal is Best Developer. "
console.log(str.replaceAll("Vishal", "Sujit")); // "Sujit is Best Frontend Developer. Sujit is Best Developer. "
```
### Substring of a String
```javascript
console.log(str.substring(6, 30));
console.log(str.slice(-10, -1));
```
### Split and Join
```javascript
console.log(str.split(""));
const subString = str.split(" ");
console.log(subString.join(" "));
```
### String Start and End
```javascript
console.log(str.startsWith("Vishal")); // true
console.log(str.endsWith("Developer")); // true
```
### Trim and Case Conversion
```javascript
const trimStr = str.trim();
const trimStrStart = str.trimStart();
const trimStrEnd = str.trimEnd();
console.log(trimStr, trimStr.length);
console.log(str.toLowerCase());
console.log(str.toUpperCase());
```
### Convert Number and Object to String
```javascript
const num = 123;
console.log(num, num.toString());
const obj = {
name: "Vishal",
course: "DSA with Vishal"
};
console.log(obj, JSON.stringify(obj));
```
### Concatenate Strings
```javascript
const lastName = "Rajput";
console.log(firstName + lastName);
console.log(`${firstName} ${lastName} is a Best Developer`);
console.log(firstName.concat(lastName, " is a", " Best"));
```
## Practice Questions
- [Find the Index of the First Occurrence in a String](https://leetcode.com/problems/find-the-index-of-the-first-occurrence-in-a-string/)
- [Reverse String](https://leetcode.com/problems/reverse-string)
- [Valid Anagram](https://leetcode.com/problems/valid-anagram)
- [Longest Common Prefix](https://leetcode.com/problems/longest-common-prefix)
- [Merge Strings Alternately](https://leetcode.com/problems/merge-strings-alternately)
- [Length of Last Word](https://leetcode.com/problems/length-of-last-word/)
- [Valid Palindrome](https://leetcode.com/problems/valid-palindrome)
- [String Compression](https://leetcode.com/problems/string-compression)
- [Reverse Words in a String](https://leetcode.com/problems/reverse-words-in-a-string)
- [Reverse Vowels of a String](https://leetcode.com/problems/reverse-vowels-of-a-string)
- [Rotate String](https://leetcode.com/problems/rotate-string)
[String In JavaScript]
![[String In JavaScript]](https://img.youtube.com/vi/Unc365YFdf4/0.jpg){kind=link}