How can I use filter and map in JavaScript effectively?

How can I use filter and map in JavaScript effectively?

You can use filter to create a new array with elements that pass a test, and map to transform each element.

Can you give me an example of using both filter and map together?

Sure! Let's say you have an array of numbers and you want to double only the even numbers. You can do this:

const numbers = [1, 2, 3, 4, 5, 6];
const result = numbers.filter(num => num % 2 === 0).map(num => num * 2);
console.log(result); // [4, 8, 12]

What if I want to use them on an array of objects?

You can still use filter and map on arrays of objects. For example, if you have an array of users and want to get the names of users older than 18:

const users = [{name: 'Alice', age: 22}, {name: 'Bob', age: 17}, {name: 'Charlie', age: 19}];
const names = users.filter(user => user.age > 18).map(user => user.name);
console.log(names); // ['Alice', 'Charlie']