How to use JSON API to update a specific value in a multi-value field?

If using PATCH, the request would include all unchanged values, for example:

curl -X PATCH \
-H 'Content-Type: application/vnd.api+json' \
--user user:password \
https://master-6hplc6fufbi9r9qm4cpm32byiowejoz4.tugboatqa.com/jsonapi/node/recipe/1ccd8b1b-b09b-405c-ad44-e1aadb1bc880 \
-d '{"data":{"id":"1ccd8b1b-b09b-405c-ad44-e1aadb1bc880","type":"node--recipe","attributes":{"field_ingredients":[{"value":"For the pastry:"},{"value":"299g plain flour"},{"value":"140g butter"},{"value":"Cold water"},{"value":"For the filling:"},{"value":"1 onion"},{"value":"2 garlic cloves"},{"value":"Half a courgette"},{"value":"450ml soya milk"},{"value":"500g grated parmesan"},{"value":"2 eggs"},{"value":"200g sun dried tomatoes"},{"value":"100g feta"}]}}}'

Seems like there could be a way to use POST similar to #2996339: Adding a new value to a multi-value relationship field without losing existing data →

Drupal 9 is no longer supported.

So, probably the answer will be the same, but if anything turns out to be specific to Drupal 9, everyone will say "upgrade the site".

Right, I used that version b/c simplytest.me site was using 9.5 by default.

My use case would be for the latest version.

I changed the version in case its used to filter out issues if that matters.

Based on support from Drupal slack,

https://git.drupalcode.org/project/drupal/-/blob/10.2.x/core/modules/jso....

EntityResource::patchIndividual()

and

EntityResource::updateEntityField()

There isn't a way to target a specific delta of a multivalue field value.

In the scenario I found myself in, which I've concluded is a poor design, was preventing race conditions from an application updating the same resource from different browser tabs. Since posting, my research has lead me to use a different model to ensure operations don't step on each other.

Automatically closed - issue fixed for 2 weeks with no activity.