Add example for testing null field in flow condition

[jbmolle]

Page

https://docs.directus.io/reference/filter-rules.html#filter-operators

Describe the Inaccuracy

Hi, Maybe I picked the wrong doc page and it should be in Guiides -> Flow as an example. I was trying to test if a slug field was null in a flow so I used the following condition:

{
    "$trigger": {
        "payload": {
            "slug": {
                "_null": true
            }
        }
    }
}

The condition would pass with the payload { "slug": null } but it would fail with the payload {} because of the requireAll property in directus/api/src/operations/condition/index.ts I would expect the validation to succeed when the field is missing. But I know that there were other problems when the requireAll property was missing.

So finally I've came up with this solution:

{
    "$trigger": {
        "payload": {
            "slug": {
                "_nnull": true
            }
        }
    }
}

Now the condition succeeds when the field exists and is not null and it fails otherwise. So I execute the rest of the flow when the condition fails. I just thought that this example could be written somewhere and that the doc indicates that all the fields in condition are required in the payload.

[ched-dev]

You could also use _empty or _nempty if you want to check whether it has a value or not.

Could you write some documentation to describe what you think is missing? I've submitted several documentation fixes and the team is happy to look at them.

[linear[bot]]

EDU-346 Add example for testing null field in flow condition