Cleanup navigation related code

[tomalec]

Describe the bug:

Currently, navigation-related code is scattered around our codebase in multiple places. It makes it hard to add new pages or change the navigation flow. Some of it is a result of Woo convention of adding pages - separate setup in PHP separate in JS. But I believe some of it could be cleaned up on our end.

Here is the list of places when we define the navigation:

1. All /src/Menu/*.php
2. /js/src/index.js
3. /js/src/utils/urls.js - List of internal URLs to be used in links, buttons, etc.
   • even within that file we have redundant entries 💅 Simplify .~/utils/urls.js #1024
4. /js/src/components/navigation-classic/main-tab-nav.js
   • a workaround to highlight "current" page in the legacy WC menu
   • list of main tabs

Thoughts, doubts:

• I'm not entirely sure, what is the relation between 1. (/src/Menu/*.php) and 2. (/js/src/index.js), and if the 2. will be needed in the new nav. Also, why it cannot be built from a single source.

• I have a gut feeling that 2. (/js/src/index.js) and 3. (/js/src/utils/urls.js) could somewhat share the config.

• I think, the hack for legacy nav highlighting could be move from 4. /js/src/components/navigation-classic/main-tab-nav.js somewhere else, as it's easy to miss it. (Current, settings subpages & account-reconnection, do not use it). Also, we could use a somewhat more official window.wpNavMenuClassChange instead of manually hacking CSS selectors and classes.
  (Personally, I spend a week working with navigation. Then needed an entire day of debugging the WC-admin navigation to find it.)

  • Separate legacy WC menu handling to a separate hook, #1038
  • Update the WP-admin menu highlight, after navigation #1049