Top JavaScript String Functions with example

list of 45 JavaScript string functions with examples :

### 1. `charAt()`
Returns the character at a specified index.
```javascript
let str = "Hello";
console.log(str.charAt(0)); // "H"
```

### 2. `charCodeAt()`
Returns the Unicode of the character at a specified index.
```javascript
let str = "Hello";
console.log(str.charCodeAt(0)); // 72
```

### 3. `concat()`
Joins two or more strings.
```javascript
let str1 = "Hello";
let str2 = " World";
console.log(str1.concat(str2)); // "Hello World"
```

### 4. `includes()`
Checks if a string contains a specified substring.
```javascript
let str = "Hello World";
console.log(str.includes("World")); // true
```

### 5. `endsWith()`
Checks if a string ends with a specified substring.
```javascript
let str = "Hello World";
console.log(str.endsWith("World")); // true
```

### 6. `indexOf()`
Returns the index of the first occurrence of a specified value.
```javascript
let str = "Hello World";
console.log(str.indexOf("o")); // 4
```

### 7. `lastIndexOf()`
Returns the index of the last occurrence of a specified value.
```javascript
let str = "Hello World";
console.log(str.lastIndexOf("o")); // 7
```

### 8. `match()`
Searches a string for a match against a regular expression.
```javascript
let str = "Hello World";
console.log(str.match(/o/g)); // ["o", "o"]
```

### 9. `replace()`
Replaces a specified value with another value in a string.
```javascript
let str = "Hello World";
console.log(str.replace("World", "JavaScript")); // "Hello JavaScript"
```

### 10. `search()`
Searches a string for a match against a regular expression and returns the index.
```javascript
let str = "Hello World";
console.log(str.search("World")); // 6
```

### 11. `slice()`
Extracts a part of a string and returns it as a new string.
```javascript
let str = "Hello World";
console.log(str.slice(0, 5)); // "Hello"
```

### 12. `split()`
Splits a string into an array of substrings.
```javascript
let str = "Hello World";
console.log(str.split(" ")); // ["Hello", "World"]
```

### 13. `startsWith()`
Checks if a string starts with a specified substring.
```javascript
let str = "Hello World";
console.log(str.startsWith("Hello")); // true
```

### 14. `toLowerCase()`
Converts a string to lowercase letters.
```javascript
let str = "Hello World";
console.log(str.toLowerCase()); // "hello world"
```

### 15. `toUpperCase()`
Converts a string to uppercase letters.
```javascript
let str = "Hello World";
console.log(str.toUpperCase()); // "HELLO WORLD"
```

### 16. `trim()`
Removes whitespace from both ends of a string.
```javascript
let str = "   Hello World   ";
console.log(str.trim()); // "Hello World"
```

### 17. `substring()`
Returns a part of the string between two specified indices.
```javascript
let str = "Hello World";
console.log(str.substring(0, 5)); // "Hello"
```

### 18. `toString()`
Returns the string value of an object.
```javascript
let num = 123;
console.log(num.toString()); // "123"
```

### 19. `valueOf()`
Returns the primitive value of a string object.
```javascript
let str = new String("Hello");
console.log(str.valueOf()); // "Hello"
```

### 20. `localeCompare()`
Compares two strings in the current locale.
```javascript
let str1 = "apple";
let str2 = "banana";
console.log(str1.localeCompare(str2)); // -1
```

### 21. `repeat()`
Returns a new string with a specified number of copies of the original string.
```javascript
let str = "Hello";
console.log(str.repeat(3)); // "HelloHelloHello"
```

### 22. `fromCharCode()`
Returns a string created from the specified sequence of UTF-16 code units.
```javascript
console.log(String.fromCharCode(72, 101, 108, 108, 111)); // "Hello"
```

### 23. `padStart()`
Pads the current string with another string (repeated, if needed) until the resulting string reaches the given length.
```javascript
let str = "5";
console.log(str.padStart(2, "0")); // "05"
```

### 24. `padEnd()`
Pads the current string with another string until the resulting string reaches the given length.
```javascript
let str = "5";
console.log(str.padEnd(2, "0")); // "50"
```

### 25. `trimStart()`
Removes whitespace from the beginning of a string.
```javascript
let str = "   Hello";
console.log(str.trimStart()); // "Hello"
```

### 26. `trimEnd()`
Removes whitespace from the end of a string.
```javascript
let str = "Hello   ";
console.log(str.trimEnd()); // "Hello"
```

### 27. `toLocaleLowerCase()`
Converts a string to lowercase letters, according to any locale.
```javascript
let str = "HELLO";
console.log(str.toLocaleLowerCase('tr')); // "hëllo" (Turkish locale)
```

### 28. `toLocaleUpperCase()`
Converts a string to uppercase letters, according to any locale.
```javascript
let str = "hello";
console.log(str.toLocaleUpperCase('tr')); // "HËLLO" (Turkish locale)
```

### 29. `codePointAt()`
Returns a non-negative integer that is the Unicode code point value of the character at the given position.
```javascript
let str = "𠜎";
console.log(str.codePointAt(0)); // 134071
```

### 30. `at()`
Returns the character at a specified index, allowing for negative indexing.
```javascript
let str = "Hello";
console.log(str.at(-1)); // "o"
```

### 31. `includes()`
Checks if a string contains a specified substring.
```javascript
let str = "Hello, world!";
console.log(str.includes("world")); // true
```

### 32. `replaceAll()`
Returns a new string with all matches of a pattern replaced by a replacement.
```javascript
let str = "Hello World";
console.log(str.replaceAll("o", "0")); // "Hell0 W0rld"
```

### 33. `normalize()`
Returns the Unicode Normalization Form of the string.
```javascript
let str = "Café";
console.log(str.normalize("NFC")); // "Café"
```

### 34. `split()`
Divides a string into an array of substrings.
```javascript
let str = "a,b,c";
console.log(str.split(",")); // ["a", "b", "c"]
```

### 35. `String.raw()`
A tag function for template literals.
```javascript
console.log(String.raw`Hello\nWorld`); // "Hello\nWorld"
```

### 36. `toString()`
Returns the string value of an object.
```javascript
let str = new String("Hello");
console.log(str.toString()); // "Hello"
```

### 37. `search()`
Searches a string for a match against a regular expression and returns the index.
```javascript
let str = "Hello World";
console.log(str.search(/o/)); // 4
```

### 38. `lastIndexOf()`
Returns the index of the last occurrence of a specified value.
```javascript
let str = "Hello World";
console.log(str.lastIndexOf("o")); // 7
```

### 39. `replace()`
Replaces the first occurrence of a substring.
```javascript
let str = "Hello World";
console.log(str.replace("World", "there")); // "Hello there"
```

### 40. `startsWith()`
Checks if a string starts with a specified substring.
```javascript
let str = "Hello";
console.log(str.startsWith("He")); // true
```

### 41. `endsWith()`
Checks if a string ends with a specified substring.
```javascript
let str = "Hello";
console.log(str.endsWith("lo")); // true
```

### 42. `split()`
Splits a string into an array of substrings.
```javascript
let str = "Hello World";
console.log(str.split(" ")); // ["Hello", "World"]
```

### 43. `concat()`
Combines two or more strings.
```javascript
let str1 = "Hello";
let str2 = " World";
console.log(str1.concat(str2)); // "Hello World"
```

### 44. `indexOf()`
Returns the index of the first occurrence of a specified value.
```javascript
let str = "Hello World";
console.log(str.indexOf("o")); // 4
```

### 45. `length`
Returns the length of a string.