If you are familiar with Angular 7+, transitioning to Ionic 4+ will be a breeze.
The process is straightforward. The HTML, SCSS, and TypeScript code remains relatively unchanged.
Here's a quick overview:
Step 1: In Ionic 4+, the concept of providers has been replaced by services. To create a new page, simply run 'ionic generate page contact' and then transfer relevant code from Ionic 3 to 4. This involves copying imports, constructor functions, and code snippets.
Please note that there may be compatibility issues, but solutions are available for every problem that arises.
Step 2: Generate a service using 'ionic generate service api' and paste provider code into it.
Step 3: Address any errors that may arise during the migration process.
Step 4: Finally, build and run your application to test its functionality.