Material NumField with defaultValue cannot be cleared

[KoenLav]

When using uniforms, simpl-schema (v2) and material, all at version 3.5.1 (latest version as of writing) when we clear a NumberField (in an AutoForm with an attached schema and model) the defaultValue will be set, whereas this works fine for a TextField.

Assuming the defaultValue of a NumberField is 10, when I backspace 0 it will show 1, but once I backspace 1 it will show 10 again.

Playground example

I believe these lines combined may be the culprit (setting the value to undefined instead of empty string will cause value to be set to initialValue):
https://github.com/vazco/uniforms/blob/master/packages/uniforms-material/src/NumField.tsx#L50
https://github.com/vazco/uniforms/blob/master/packages/uniforms/src/useField.tsx#L85

[radekmie]

Hi @KoenLav. That's a great finding! I'm actually surprised that no one has ever reported it earlier. When it comes to fixing that, it's a little problem. Changing the initialValue logic is a really important breaking change. The same goes for adjusting the NumFields of all themes (yes, it affects all themes).

I'm just thinking, what would be the best here. Maybe wrapping this code with a if (!changed) condition would be fine...? We'll have to check it.

[KoenLav]

Looking at the code: if changedMap contains all fields which no longer have their original value, then changed will only be false if we haven't modified a field, so !changed will only be trur when we have changed a field, in which case we don't want to set te value indeed.

[KoenLav]

However, I think initialValue should still be set (I don't think it matters much, but for consistency).

So maybe instead of initialValue = value, set initialValue using getInitialValue and only set value if !changed?

[radekmie]

Well, that's not the changed/changedMap works. It stores the information on whether the value has ever changed, not whether it differs from the original one. It's still a breaking change though.