The Missing Introduction to JavaScript

Question 1

Why is JavaScript considered an Interpreted language?

Answer 1

JavaScript is considered an Interpreted language because it does not need to be compiled to be executed. Interpreted languages are translated to machine code upon execution.

Question 2

Why is JavaScript considered a Multi-paradigm language?

Answer 2

JavaScript is considered a Multi-paradigm language because it supports multiple styles of coding, including:
* Imperative
* Procedural
* Object-oriented
* Prototypal inheritance, and
* Functional

Question 3

At a high level, what is ECMAScript?

Answer 3

ECMAScript is a specification, or body of standards, that JavaScript conforms to.

Question 4

What is ES5?

Answer 4

ES5 is short for ECMAScript 5, and is the 2009 release version of ECMAScript standards, the latest version that is fully supported in all modern browsers.

Question 5

What is Babel?

Answer 5

Babel is a transpiler that compiles ES2015 (aka ES6) JavaScript into ES5 JavaScript to ensure full support across all modern browsers.

Question 6

What is a JavaScript Engine?

Answer 6

A JavaScript Engine is the software that actually runs JavaScript code.

Whereas traditionally JavaScript engines would interpret JS code, many modern JS Engines translate JS code into machine code, such as the Google Chrome V8 Engine, which uses a Just-In-Time Compiler (aka JIT) to run code.

Question 7

At a high level, what is Node.js?

Answer 7

Node.js essentially moved Chrome’s V8 engine outside of the browser, allowign it to run on other platforms. This allows us to write JS on both the front-end and back-end of an application.

Question 8

At a high level, what is the Document-Object-Model?

Answer 8

The Document-Object-Model (aka the DOM) is an API for HTML and XML documents which provides us a structural representation of the document so that we can interact with it via JavaScript.

Question 9

What are Packages and what is Package management?

Answer 9

Packages (aka Modules) are distinct projects containing specific functionality that can be imported into other code bases to implement that functionality. A Package manager helps us manage the packages we want to use in our project.

NPM is the most popular package manager for JavaScript.

Question 10

What is a Local HTTP server?

Answer 10

A Local HTTP server allows developers to serve code locally and includes services such as live-reload (i.e.compilation upon file save), and allows us to make HTTP requests to a server.

Node.js is what allows us to run a local development server with JS.

Question 11

What is Webpack?

Answer 11

Webpack is a module bundler that combines our JavaScript code and dependencies together into a single file.

It also handles advanced techniques such as code splitting (aka lazy loading).

Question 12

What is Linting?

Answer 12

Linting refers to the process of analyzing code on the fly to pick up potential errors.

ESLint is the most popular linter used for JavaScript.

Question 13

What is a package.json file?

Answer 13

A package.json file is a file that lists our packages and the versions we would like to install.

Packages are installed by running the CLI command npm install <dependency name>.

The CLI command npm init creates the package.json file.

Question 14

What is the **node_modules** folder?

Answer 14

The node_modules folder is created when we install our dependencies with the CLI command npm install, and is where downloaded packages are saved.