What is ionic framework

Ionic Framework is an open source UI toolkit for building high-quality well performing mobile and desktop apps using web technologies (HTML, CSS, and JavaScript).Ionic Framework is focused on the frontend user experience, or UI interaction of an app (controls, interactions, gestures, animations). It’s easy to learn, and integrates nicely with other libraries or frameworks, such as Angular, or can be used standalone without a frontend framework using a simple script include.

Ionic 3 vs ionic 4:

1.There are great changes in the navigation and in the Router, which are a big update.
2. Ionic 3 used a navigation based on a simple stack where the new pages were pushed on top of the stack and when we wanted to navigate backwards we simply made a pop of the last page.
3. In Ionic 4 The Angular Router is one of the most important libraries from an Angular application. Without it, apps would not be able to maintain their navigation state on browser reloads.

Purpose of Ionic Framework

Cross platform:

Ionic provides an environment to build and deploy apps that work across multiple platforms, such as native iOS, Android, desktop, and the web. Write once the code run anywhere.

Web standard based:

 Ionic Framework is built on top of reliable, standardized web technologies: HTML, CSS, and JavaScript, using modern Web APIs such as Custom Elements and Shadow DOM

Beautiful design:

Ionic Framework is designed to work and display beautifully  across all platforms. Available pre-designed components, typography, interactive paradigms, and attractive base theme.

Angular

Angular is a platform and framework for building client applications in HTML and TypeScript. Angular is written in TypeScript. It implements core and optional functionality as a set of TypeScript libraries that you import into your apps.
The basic building blocks of an Angular application are NgModules, which provide a compilation context for components. NgModules collect related code into functional sets; an Angular app is defined by a set of NgModules.

What is ionic CLI?

The Ionic CLI is built with TypeScript and Node.js.

CLI is a inbuilt tool provide interface to developer such as installing and updating Ionic, the CLI comes with a built-in development server, build and debugging tools, and much more.

What is TypeScript ?:

TypeScript is a primary language for Angular application development. It is a superset of JavaScript with design-time support for type safety and tooling. Browsers can't execute TypeScript directly. It must be "transpiled" into JavaScript using the tsc compiler.

What is Node.js:

Node.js is a open source server environment and allow to run javascript on the server.With Node.js javascript extends its capability not only to run on a browser but also on your machine as a standalone application.Both your browser JavaScript and Node.js run on the V8 JavaScript runtime engine. This engine takes your JavaScript code and converts it into a faster machine code or low-level code which the computer can run without interpreting it.