Power Tools: Arrow Functions & Array Methods

Enemy 1 of 5

You've already defined functions with the function keyword. Arrow functions are a newer, shorter way to write the same idea: (params) => expression. For a single expression, the result is returned automatically — no return keyword and no curly braces needed at all, which makes short, one-off functions much less noisy to write.

Arrow functions are used constantly in modern JavaScript, especially as arguments to other functions — you'll see this immediately in .map() and .filter() below. One quirk worth knowing: arrow functions handle the this keyword differently from regular functions, which matters once you're writing methods inside classes or objects, though it rarely comes up in code this simple.