WP-5258 Automatically use sockjs_client_wrapper if possible.

[evanweible-wf]

Changes

With the release of sockjs_client_wrapper, we want to use that library if possible because it is fully featured and supports all of the SockJS protocols (particularly xhr-polling). But, we can't just switch because it requires the addition of the sockjs.js library to the HTML page.

The proposed solution here is to check for the existence of the sockjs.js script by checking for SockJS on the window. If it's there, we'll automatically leverage the new package instead of the old Dart port. Otherwise, we'll fallback to the original behavior (i.e. nothing should change).

Testing

• CI passes
• Follow testing instructions here: https://github.com/Workiva/wdesk_sdk/pull/2037

Code Review

@Workiva/app-frameworks

[aviary2-wf]

Raven

Number of Findings: 0

[jacehensley-wf]

Thoughts on spitting out a hint about using the new lib?

[evanweible-wf]

I added a note to the changelog, the source docs for WebSocket, and the SockJS guide. I'd rather not log/print anything right now since I don't see us making the major jump anytime soon and in the meantime it's valid for consumers to not want to change anything since it still works.

[codecov-io]

Codecov Report

Merging #296 into master will increase coverage by 1.6%.
The diff coverage is 94.66%.

[jayudey-wf]

QA +1

• Testing instruction
• Dev +1's
• Dev/QA +10 with detail of what was tested
  • verified in the wdesk example that it was still able to function
  • verified in echo example that messages were still able to be sent
• Security review (if required)
• Unit tests created/updated
• All unit tests pass
• Rosie has run and reports properly the release the ticket will be included in

Merging into master.