Repeated code between server `previewGeneration.js` and client `EmbedFrame.jsx`

[lindapaiste]

Increasing Access

Our codebase becomes more maintainable if functions are defined in one place only.

Feature enhancement details

I noticed that there is a function resolvePathsForElementsWithAttribute which is identical in both files. Other parts of the code are similar but different.

Tasks:

• Look at the Git history for each file and read any discussions on the PRs and issues that led to changes.
• Reuse functions from the server code in the client component instead of recreating it.
• Add explanatory comments in the code.
• Add unit tests.
• Make improvements to the code itself, for example using RegExp test() to check for truthiness rather than match() !== null.

Questions:

• Which parts of the code are the same and can be reused?
• For the parts which differ, is the difference due to necessity of the client vs server environment?
• Do we even need the server version at all? This code was previously used for the /embed/ endpoints, but those are disabled right now due to phishing concerns. I'm not sure what it would take for us to re-enable it. It might make sense to delete it. See Bug/phishing #1967, Restore Present view that doesn't allow phishing #1971, etc. for background.