Arrays are generally described as "list-like objects"; they are basically single objects that contain multiple values stored in a list. Array objects can be stored in variables and dealt with in much the same way as any other type of value, the difference being that we can access each value inside the list individually, and do super useful and efficient things with the list, like loop through it and do the same thing to every value. Maybe we've got a series of product items and their prices stored in an array, and we want to loop through them all and print them out on an invoice, while totaling all the prices together and printing out the total price at the bottom.

What is an array?

JavaScript is primarily an object-oriented language, where many built-in features such as arrays and browser APIs are objects themselves. Additionally, developers can create their own objects to organize functions and variables into reusable packages. Understanding the object-based structure of JavaScript is crucial for advancing one's understanding of the language. This module aims to provide a comprehensive overview of object theory, syntax, and how to create custom objects.

Introducing JavaScript objects

The async function* keywords can be used to define an asynchronous generator function inside an expression.
```js
async function* foo() {
  yield await Promise.resolve('a');
  yield await Promise.resolve('b');
  yield await Promise.resolve('c');
}

let str = '';

async function generate() {
  for await (const val of foo()) {
    str = str + val;
  }
  console.log(str);
}

generate();
// Expected output: "abc"
```

async function* expression

when a web page is loaded in a browser, the code (HTML, CSS, and JavaScript) is executed within the browser tab, which acts like a factory that takes in the code and produces the web page. One common use of JavaScript is to change the HTML and CSS in order to update the user interface using the Document Object Model API. It is important to note that the code is generally loaded and executed in the order it appears on the page and errors may occur if JavaScript is run before the related HTML and CSS. 

Stanford University

JavaScript is a lightweight, interpreted or just-in-time compiled, programming language with first-class functions. It is a prototype-based, multi-paradigm, single-threaded, dynamic language that supports object-oriented, imperative, and declarative programming styles, such as functional programming. It was invented by Brendan Eich in 1995 at Netscape and later continued to be developed under the ECMA standard by the Mozilla Foundation.

JavaScript Programming Language

https://developer.mozilla.org/

What is JavaScript doing on your page?

React is a user interface library that was created by Jordan Walke at Meta. It was first deployed on Facebook's News Feed in 2011 and later on Instagram in 2012. 

React is based on components, allowing you to divide views into smaller pieces of logic and view, and reuse them. React is declarative, allowing you to create simple views and React will render them efficiently. Data is passed in one direction. React has many features such as the Virtual DOM, Lifecycle Methods, JSX, and React Hooks.

React Js

React documentation

JavaScript is case-sensitive and uses the Unicode character set. An instruction is called a statement. We can separate statements with a semicolon, although it is not required if a statement is on one line.

The basic concepts in JavaScript include: 
- Comments
- Declarations
- Variables
- Data structures and types
- Literals

Grammar and types

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Grammar_and_types

JavaScript - Grammar and types

Node.js, created by Ryan Dahl and first released in 2009, is an open-source server environment designed to run on multiple platforms, including Windows, Linux, Unix, and macOS. It is a back-end JavaScript runtime environment that uses the V8 JavaScript engine to execute JavaScript code outside of a web browser. With Node.js, developers can create command-line tools and server-side scripts using JavaScript. By enabling scripts to run server-side, Node.js allows for the creation of dynamic web page content before it is sent to the user's browser. This approach unifies web application development by promoting the use of a single programming language across both server-side and client-side scripts.

Learn Before

Related

Learn After