This project is based on dynamic theme modification by clicking the buttons, changing different color values. Some part of the code is taken by Ionic 4 page, and adapted into Ionic 3. New document page is returned after the code is run, but current document is not replaced with the old one.
An example is shown below:
There are three themes, as indicated in buttons. As shown in the GIF, the new documents are returned but not set to the current document.