JavaScript

Node.js is a runtime environment, basically where code can be executed in a lifecycle, allowing JavaScript to run server-side. Its main features are its event based model and asynchronous request handling.

Node.js is not a framework. A framework describes a set of tools for development. For example, Express is a JavaScript framework in that it is a collection of tools to build web applications with. In contrast, Node.js’s primary task is to compile and run code.

Essentially let and const cannot be used before they are initialized, unlike var. Additionally, they are tied down by their block scope, which var is not.

Promise.all()

Callbacks are when a function ends in calling another function. Asynchronous programming is when are able to have several processes running in tandem rather than hanging up on each one finishing.

The “try” aspect of the block tries to run code, while “catch” allows for error handling to be manually implemented.

It is an inheritance of another class object, so that it has the properties of the “parent” class.