JavaScript provides several powerful string methods that help developers manipulate and process text efficiently. These JavaScript string methods allow you to modify, search, split, and transform strings, making them essential for web development. In this guide, we will explore the top 10 JavaScript string methods you should know in 2025.
1. length;
In JavaScript string, the length method is used to return the number of characters in the string.
Example:
const name = “Anmol”;
console.log(name.length);
Output: 5
Explanation: The length property returns the number of characters in the string, including spaces and punctuation. This method is useful when you need to know the number of characters in a string.
2. toUpperCase();
toUpperCase(): toUpperCase() JavaScript string method is used to convert all characters in the string to uppercase.
Example:
const str = “hello”;
console.log(str.toUpperCase());
Output: HELLO
Explanation: The toUpperCase() method converts all characters in the string to uppercase, including letters and characters. This method is useful when you need to standardize string data or make it more readable.
3. toLowerCase();
toLowerCase(): The toLowerCase() JavaScript string methods is used to convert all the characters in the string to lowercase.
Example:
const str = “HELLO”
console.log(str.toLowerCase());
Output: hello
Explanation: The toLowerCase() method converts all characters in the string to lowercase, including letters and characters. This method is useful when you need to standardize string data or make it more readable.
4. trim();
trim(): JavaScript trim() method in string is used to remove the whitespace from the beginning and end of the string.
Example:
const str = ” hello world “;
console.log(str.trim());
Output: hello world
Explanation: The trim() method removes whitespace from the beginning and end of the string, but not from the middle. This method is useful when you need to clean up user input or remove unnecessary whitespace.
5. split();
split(): The split string method is used to convert the string into an array of substrings based on a separator.
Example:
const str = “hello,world,foo,bar”;
console.log(str.split(“,”));
Output: [“hello”, “world”, “foo”, “bar”]
Explanation: The split() method splits the string into an array of substrings based on a separator, such as a comma or space. This method is useful when you need to break up a string into smaller parts or extract specific data.
6. join();
join(): As the name suggests the joins() method is used to join an array of strings into a single string.
Example:
const str = [“hello”, “world”];
str = str.join(” “);
console.log(str);
Output: hello world
Explanation: The join() method joins an array of strings into a single string, using a separator such as a space or comma. This method is useful when you need to combine multiple strings into one.
7. replace();
replace(): The replace method in JavaScript string is used to replace a portion of the string with another string.
Example:
const stri = “hello world”;
str = str.replace(“world”, “JavaScript”);
Output: hello JavaScript
Explanation: The replace() method replaces a portion of the string with another string, using a regular expression or string. This method is useful when you need to update or modify specific parts of a string.
8. indexOf();
indexOf(): The indexOf() method in JavaScript string is used to return the index of the first occurrence of a specified value.
Example:
const stri = “hello world”
console.log(stri.indexOf(“world”));
Output: 6
Explanation: The indexOf() method returns the index of the first occurrence of a specified value, such as a character or substring. This method is useful when you need to find the position of a specific character or substring.
9. includes();
includes(): This JavaScript string method returns a boolean value, indicating whether the string contains a specified value. If the string contains the value then it will return true else it will return false.
Example:
const str = “hello world”;
console.log(str.includes(“world”));
Output: true
Explanation: The includes() method returns a boolean indicating whether the string contains a specified value, such as a character or substring. This method is useful when you need to check if a string contains specific text.
10. substring();
substring(): The substring() method in JavaScript string, returns a portion of the string between two specified indices.
Example:
const str = “hello world”;
console.log(str.substring(0, 5));
Output: hello
Explanation: The substring() method returns a portion of the string between two specified indices, such as the start and end of a substring. This method is useful when you need to extract a specific part of a string.
If you want to learn more about JavaScript string methods, check out my detailed guide on my website. Also, don’t forget to visit my YouTube channel for video tutorials on JavaScript and frontend development.