Remove the PersistentCache functionality

[kieran-sf]

Description

The Managed Runtime team has removed the PersistentCache functionality on our platform. These changes are to remove the PersistentCache functionality in the PWA Kit before removing the entire PersistentCache feature in a future release.

Types of Changes

Removing the underlying PersistentCache functionality.

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Documentation update
• Breaking change (could cause existing functionality to not work as expected)
• Other changes (non-breaking changes that does not fit any of the above)

Changes

• Remove PersistentCache functionality
• Update tests

How to Test-Drive This PR

• Add the cache code (below) to the template-retail-react-app ssr.js
• Deploy these changes to a storefront and hit the cache endpoints. They should all work with the get always not found
  • /get?k=key
  • /put?k=key&v=value
  • /delete?k=key

Code

app.get('/get', (req, res) => {
    const k = req.query.k
    app.applicationCache
        .get({key: k})
        .then((e) => {
            res.send(e)
        })
        .catch((e) => {
            console.error(e), res.send(e)
        })
})
app.get('/put', (req, res) => {
    const k = req.query.k
    const v = req.query.v
    app.applicationCache
        .put({key: k, data: v})
        .then((e) => {
            console.log(e), res.send(`PUT ${k}: ${v}`)
        })
        .catch((e) => {
            console.error(e), res.send(e)
        })
})
app.get('/delete', (req, res) => {
    const k = req.query.k
    app.applicationCache
        .delete({key: k})
        .then((e) => {
            console.log(e), res.send(`DELETE ${k}`)
        })
        .catch((e) => {
            console.error(e), res.send(e)
        })
})

General

• Changes are covered by test cases
• CHANGELOG.md updated with a short description of changes (not required for documentation updates)

Accessibility Compliance

You must check off all items in one of the follow two lists:

• There are no changes to UI

or...

• Changes were tested with a Screen Reader (iOS VoiceOver or Android Talkback) and had no issues
• Changes comply with WCAG 2.0 guidelines levels A and AA
• Changes to common UI patterns and interactions comply with WAI-ARIA best practices

Localization

• Changes include a UI text update in the Retail React App (which requires translation)

[bfeister]

Are we sure we want to test the non-existence of a deprecated feature? If "yes" is the answer, how do we define a time when we would deem it safe (in the future) to delete this test?

[bfeister]

These changes are to remove the PersistentCache functionality in the PWA Kit before removing the entire PersistentCache feature in a future release.

Ok, so we're removing from PWA Kit but leaving in MRT temporarily? I thought it was already verified that no existing customer implementation is using the feature (per previous conversation)?

[kieran-sf]

I left the tests in there currently because I didn't want the test coverage to drop and then have to make it up in other places, but I am fine with removing all the tests and bringing down the coverage level.

I'll update the description to be more clear but we have already removed it from the managed runtime. The managed runtime team discussed removing the functionality of it from the PWA Kit first so not to make a breaking change and then in a future V3 release would remove the code entirely.

[kieran-sf]

One other thing I forgot to mention is that I left the tests in there as well because they cover pieces that surround the PersistentCache feature there are unchanged sendCachedResponse, cacheResponseWhenDone, getResponseFromCache. Those functions are unchanged (but they won't do anything since the cache no longer works).

[bfeister]

You've got some failing tests here @kieran-sf

[wjhsf]

👍 for getting rid of the arbitrary precision
👎 for smaller number
🫠 I'm so conflicted!

[wjhsf]

Suggested change

	expect(error.mock.calls).toEqual([['Uncaught exception: ', '(no error)']])
	expect(error).toHaveBeenCalledTimes(1)
	expect(error).toHaveBeenCalledWith('Uncaught exception: ', '(no error)')

Don't need to poke jest internals. 😉