[Lens] Add value count

[flash1293]

Fixes #74910

By adding value count to the existing count function in Lens (picking another field than records).

AggConfig changes

Add value count as any other aggconfig type

Lens changes

If the count function is picked, it's auto-picking the records field if there is no other field available (otherwise the user would be forced to make a pick). If coming from another field based function like average, it is keeping the selected field. On the formula, no field means record field - required to adjust some bits as they used to differentiate between field and no field, now the same branches differentiate between field and optional field.

[elasticmachine]

Pinging @elastic/kibana-vis-editors @elastic/kibana-vis-editors-external (Team:VisEditors)

[stratoula]

LGTM, this works great!
One question: Does it make sense to change the label from Value count of field to Count of field values or something like that. I find this value count of difficult to understand but it can only be me!

[flash1293]

Good suggestion @stratoula , I added it to our next sync to discuss - no strong opinion from my side

[KOTungseth]

For the definition, can we change this to:

The total number of documents. When you provide a field as the first argument, the total number of field values is counted. Use the count function for fields that have multiple values in a single document.

Examples:

To calculate the total number of documents, use count().

To calculate the number of products in all orders, use count(products.id).

To calculate the number of documents that match a specific filter, use count(kql=price > 500).

[flash1293]

Thanks @KOTungseth , adjusted

[kibana-ci]

💚 Build Succeeded

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• Commit: 1fdc473
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Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
data	514	516	+2

Public APIs missing comments

Total count of every public API that lacks a comment. Target amount is 0. Run node scripts/build_api_docs --plugin [yourplugin] --stats comments for more detailed information.

id	before	after	diff
data	2413	2421	+8

Async chunks

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

id	before	after	diff
lens	1.2MB	1.2MB	+1.2KB

Canvas Sharable Runtime

The Canvas "shareable runtime" is an bundle produced to enable running Canvas workpads outside of Kibana. This bundle is included in third-party webpages that embed canvas and therefor should be as slim as possible.

id	before	after	diff
module count	4933	4935	+2

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
data	424.2KB	426.9KB	+2.7KB

Unknown metric groups

API count

id	before	after	diff
data	3086	3094	+8

History

• 💛 Build #59355 was flaky b8adc95
• 💚 Build #59039 succeeded 82b45b6
• 💚 Build #58562 succeeded ec42e74
• 💔 Build #58535 failed d517888
• 💔 Build #58529 failed d6e1057
• 💔 Build #58171 failed 109daa2

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@elasticmachine merge upstream

[Dosant]

new value_count agg lgtm 👍