javascript-array-methods.md

Array methods

A list of all array methods can be found on MDN

Array.from()

Creates a shallow copy from an array-like or iterable object.

Array.from("foo") // returns ["f", "o", "o"]

Array.isArray()

Determines if the argument passed in is an array. Returns a boolean value.

Array.isArray([1, 2, 3]) // returns true
Array.isArray('Is a string an array?') // returns false

Array.prototype.concat()

Merge two or more arrays.

const names = ['Alice', 'Bob']
const moreNames = ['Charlie', 'Daphne']
const allNames = names.concat(moreNames)

You can also use the spread operator in ES6

const names = ['Alice', 'Bob']
const moreNames = ['Charlie', 'Daphne']
const allNames = [...names, ...moreNames] // ['Alice', 'Bob', 'Charlie', 'Daphne']

Array.prototype.splice()

Inserts a new element into a specific place in an array.

const months = ['Jan', 'March', 'April']
months.splice(1, 0, 'Feb') // ['Jan', 'Feb', 'March', 'April']

Deletes an element in an array.

const months = ['Jan', 'Feb', 'March', 'April', 'May']
months.splice(4, 1,) // ['Jan', 'Feb', 'March', 'April']

Replaces an element in an array.

const months = ['Jan', 'Feb', 'March', 'April', 'June']
months.splice(4, 1, 'May') // ['Jan', 'Feb', 'March', 'April', 'May']