What does the slice() method do in JavaScript, and how do I use it with strings?

Hello agegnw, really nice question.

In JavaScript, slice() is used to take a part of a string and return it as a new string, without changing the original one.

It works with indexes (positions of characters in the string). JavaScript starts counting from 0.

Basic form:

string.slice(startIndex, endIndex)

• startIndex → where to start (included)

• endIndex → where to stop (excluded). If you leave this out, it goes to the end of the string.

Example:

let text = "JavaScript is fun!";

let part1 = text.slice(0, 10);   // from index 0 to 9
console.log(part1);              // "JavaScript"

let part2 = text.slice(11);      // from index 11 to the end
console.log(part2);              // "is fun!"

In the kind of example from your lesson, you might see something like:

let name = "  alice  ";
let trimmed = name.trim();       // "alice"
let result = trimmed[0].toUpperCase() + trimmed.slice(1);
console.log(result);             // "Alice"

Here:

• trim() removes spaces at the start and end.

• slice(1) takes the string from index 1 onward ("lice"), so you can rebuild "Alice".

So you can think of it this way:

• trim() → cleans spaces from the ends.

• slice() → cuts out the piece of the string you want.

If you have further questions, I'm here to help.