Updating empty values

[Guiqft]

If you clear the input of the original field, the computed interface may throw a error because [].replace cannot exists, for example.
Or, if we clear a number field, the computed value may emit a "NaN" string, instead of null.

[duydvu]

Can you give an example to reproduce this bug?

[Guiqft]

Here is a GIF showing the bug:

I think that the computed value must emit a null if the source value is null.

[Guiqft]

We also have this:

I put these logs on interface.vue:63. Seems that the other computed field emitted a 0, his expression is simple: {{ MULTIPLY(numero,2) }}.
I think we must check if the source value is null before parse the expression.

[Guiqft]

@duydvu to reproduce this, you can create these fields:

• number (numeric)
• numberx2 ({{ MULTIPLY(number, 2) }}
• text (string)
• text_slug ({{ SLUG(text) }}

When you edit the text field but leaves number empty and tries to save the item, the numberx2 calculation is triggered and returns 0 (because number(null) x 2 = 0. Then, Directus complains about you trying to get out from a item that has unsaved changes.

[duydvu]

Nope, still can't see the bugs. Which Directus version are you using? Mine is 9.10.0

[Guiqft]

Hi @duydvu! Sorry for the long time.
I can still reproduces this on a empty instance of Directus 10.5.3.
In the most basic example:

• Create a INT field my_number with simple input
• Create a INT field my_number_x2 with the computed extension {{ MULTIPLY(my_number, 2) }}

When typing any number then erasing on the source input, the computed input gives me 0 as result, but I think it should be null.

If the source is a empty value, the computed should be empty too.
This is the same cause that makes the computed field starts with 0 on the video below ("Compute If Empty" is enabled).

Screen.Recording.2023-08-21.at.17.26.21.mov