Index

Arrays

Iteration methods

reduce

map

filter

some

Some returns true if at least one element in the array passes the test implemented by the provided function.

const numbers = [1, 2, 3, 4, 5];
const hasEven = numbers.some((number) => number % 2 === 0);
console.log(hasEven); // true

splice

Operators

... spread

The spread operator takes an iterator (such as a string or array), and lets us expand it into individual elements where we can use it in a function that expects zero or more arguments, or where elements are expected.

const numbers = [1, 2, 3];
const newNumbers = [...numbers, 4];
console.log(newNumbers); // [1, 2, 3, 4]

Destructuring

Destructuring allows us to extract multiple properties from an object or multiple elements from an array and assign them to variables.

const person = {
  name: "John",
  age: 30,
  city: undefined,
};

const { name, age, city = "New York" } = person; // city is undefined, so we can set a default value
console.log(name, age); // John 30

const numbers = [1, 2, 3];
const [a, b, c] = numbers;
console.log(a, b, c); // 1 2 3