[Lens] Improve Metric formatter to support bit format

[dej611]

Summary

Fixes #152014

This PR switches the formatter in the Metric visualization type from the Intl.NumberFormat back to the numeral.js one which supports more units for the bytes and bit format types.

While fixing the referenced issue, this PR also introduced some changes in how the bytes number format is displayed to the user, mainly:

• below the 1024 threshold, the B format is used instead of the full word bytes -- see the ⚠️ below
• The k for kilo is not capitalized when using bytes as documented for binary values for the entire Kibana project -- see the ⚠️ below
• The K for kilo is capitalized when using bytes as documented documented for binary values for the entire Kibana project

Comparison table

Raw value	8.6	PR	Changes
1023 bytes			⚠️
1024 bytes			⚠️
1024 ^ 2 bytes			=
1024 ^ 6 bytes			✅
1024 ^ 9 bytes			✅
999 bits			✅
1000 bits			✅
1000 ^ 2 bits			✅
1000 ^ 6 bits			✅
1000 ^ 9 bits			✅

Checklist

Delete any items that are not applicable to this PR.

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Documentation was added for features that require explanation or tutorials
• Unit or functional tests were updated or added to match the most common scenarios
• Any UI touched in this PR is usable by keyboard only (learn more about keyboard accessibility)
• Any UI touched in this PR does not create any new axe failures (run axe in browser: FF, Chrome)
• If a plugin configuration key changed, check if it needs to be allowlisted in the cloud and added to the docker list
• This renders correctly on smaller devices using a responsive layout. (You can test this in your browser)
• This was checked for cross-browser compatibility

Risk Matrix

Delete this section if it is not applicable to this PR.

Before closing this PR, invite QA, stakeholders, and other developers to identify risks that should be tested prior to the change/feature release.

When forming the risk matrix, consider some of the following examples and how they may potentially impact the change:

Risk	Probability	Severity	Mitigation/Notes
Multiple Spaces—unexpected behavior in non-default Kibana Space.	Low	High	Integration tests will verify that all features are still supported in non-default Kibana Space and when user switches between spaces.
Multiple nodes—Elasticsearch polling might have race conditions when multiple Kibana nodes are polling for the same tasks.	High	Low	Tasks are idempotent, so executing them multiple times will not result in logical error, but will degrade performance. To test for this case we add plenty of unit tests around this logic and document manual testing procedure.
Code should gracefully handle cases when feature X or plugin Y are disabled.	Medium	High	Unit tests will verify that any feature flag or plugin combination still results in our service operational.
See more potential risk examples

For maintainers

• This was checked for breaking API changes and was labeled appropriately

[elasticmachine]

Pinging @elastic/kibana-visualizations @elastic/kibana-visualizations-external (Team:Visualizations)

[drewdaemon]

Awesome work. I'm happy to see that this change will lead to better format support and consistency with other parts of Kibana. (code review only, lmk if you want me to spin it up)

[drewdaemon]

nit: I'd probably move the number default into getFormatId.

[drewdaemon]

FWIW, I'm wondering if this is an opportunity to reconsider this decision and add a bits field formatter after all. Added an agenda item to the weekly.

[dej611]

I think it can be addressed separately as it will affect all visualization types, not just metric.

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: ce131a7

Failed CI Steps

• FTR Configs #41

Test Failures

• [job] [logs] FTR Configs #41 / Cases Configure Closure options change closure option successfully

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
expressionMetricVis	71.5KB	71.3KB	-226.0B

Unknown metric groups

ESLint disabled line counts

id	before	after	diff
securitySolution	433	436	+3

Total ESLint disabled count

id	before	after	diff
securitySolution	513	516	+3

History

• 💛 Build #114448 was flaky b74bc08

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[stratoula]

Yes let's discuss it as a separate issue. We should still merge this PR as it is a very good enhancement