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Smarter Arrays — JavaScript typing lesson

Use array methods like map, filter, and reduce efficiently.

What you'll practice

Let's learn some JavaScript superpowers for arrays: `map()` and `filter()`! They're smart ways to create new arrays.

`.map()` creates a new array by doing something to each item in the original array.
`.filter()` creates a new array with only the items that pass a test.

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📜JavaScript

Smarter Arrays

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let numbers = [1, 2, 3, 4, 5];↵
↵
let squared_numbers = numbers.map(num => num * num);↵
let even_numbers = numbers.filter(num => num % 2 == 0);↵
↵
console.log(numbers);↵
console.log(squared_numbers);↵
console.log(even_numbers);

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let numbers = [1, 2, 3, 4, 5];

let squared_numbers = numbers.map(num => num * num);
let even_numbers = numbers.filter(num => num % 2 == 0);

console.log(numbers);
console.log(squared_numbers);
console.log(even_numbers);

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