This page is under threat of constant update, since I will be looking to describe and work with every array method that I can uncover with the docs. Last update was: 5/12/2019

What is this page about?

I will be adding method after method for arrays in JavaScript, looking at browser support for each method, and comparing these vanilla JS methods (using ES6) to the library Lodash. This will be updated periodically as a long-term practice for staying fresh with basics and exploring the docs more fully at MDN.

What is an array in JavaScript?

Arrays are a type of JavaScript object, but they are considered exotic objects, since the “semantics for accessing and manipulating their properties” differ from ordinary objects. The exotic semantics for accessing and manipulating array properties are focused around property keys. The property keys of an array are known as an index, and an array index is an integer index whose “whose numeric value i is in the range +0 ≤ i < 2³² - 1.” This nonnegative range less than 2³² is the value range of the non-configurable length property of an array. This length property increases and decreases as elements are added or removed from an array, and is always numerically greater than the highest index of the array. Elements are properties that have a property name that is an array index.

The syntax of an array in JavaScript is [element₀, element₁, … , element_n]. Each element of the array has its index, starting at 0, and incrementing by 1 for every element in the array.

Short Version:

Arrays in JavaScript are objects, but they are unique objects, whose property keys are ordered indices, and have an order starting at index 0 and going up to index of 4,294,967,295. An array has a property of length, which is the total number of elements that are in the array. That means that an array can have a possible length of 0 (an empty array, with no elements), up to 4,294,967,296 (a maxxed-out array). If an array has one element, that element exists at index 0, and the array will have a length of 1.

Why did I have to learn this?

These are the basics, and it pays to sharpen the saw. Also, Lodash is a library that we use at work, and I need to familiarize myself with it, and how it differs from standard ES6 methods.