Working with Text

In JavaScript, any text data is called a String. You can create a string by wrapping text in single quotes, double quotes, or backticks.

let myName = "Himanshu Dubey";
let role = 'Software Engineer';

String Properties and Methods

JavaScript provides a ton of built-in features to manipulate strings without you having to write complex logic.

1. Length Property To find out how many characters are in a string (including spaces):

let myName = "Himanshu";
console.log(myName.length); // Outputs: 8

2. toUpperCase() and toLowerCase()

let greeting = "Hello World";
console.log(greeting.toUpperCase()); // "HELLO WORLD"
console.log(greeting.toLowerCase()); // "hello world"

3. slice() Used to extract a portion of a string. You provide the starting index and the ending index (optional). Remember, JavaScript is zero-indexed!

let channel = "Himubey Learn";
console.log(channel.slice(0, 7)); // "Himubey"

4. replace() Replaces a specified value with another value in a string.

let text = "Please visit Microsoft!";
let newText = text.replace("Microsoft", "Himubey.in");
console.log(newText); // "Please visit Himubey.in!"

There are many more methods like concat(), trim(), and split(). As a developer, manipulating text is something you will do daily!

💡 Himanshu's Tip:

Don't try to memorize every single string method. Memorize the top 5 (slice, replace, toUpperCase, split, trim) and use MDN (Mozilla Developer Network) docs for the rest. Even Senior Developers look up string methods every week!

Interview Questions

What does it mean when we say strings are "immutable" in JavaScript?
How does the slice() method handle negative indexes?
What is the difference between replace() and replaceAll()?