Array of objects data entry not working with liveOmit

[epicfaace]

Description

Array of objects data entry not working with liveOmit.

Steps to Reproduce

1. Go to this playground link
2. Type in a value for "name".

Expected behavior

The form data should be

[{name: "asdasd"}]

Actual behavior

The form data is {} -- somehow liveOmit is not adding in the data properly.

Version

1.7.0+ (latest version from master)

This seems to be a regression added by PR #1371 .

PR #1371 demo

PR #1372 demo (right before #1371)

[Tonexus]

It looks like the lodash _pick call here is causing the issue

https://github.com/mozilla-services/react-jsonschema-form/blob/20ff3b97a18c061e08bc157fd3851cf4ba7101c6/src/components/Form.js#L136-L143

According to the lodash docs, _pick will always return an object, which will mess up validation if the root type of the schema is an array.

[epicfaace]

@Tonexus hmm, thanks... Do you have a way in mind that might fix it?

[Tonexus]

I created a PR that fixes part of the issue, but I found a second problem. The current usage of _pick doesn't seem able to preserve an empty object (or an empty array) inside of an array, so your specific example will still be bugged, as the objects containing the text fields will be immediately removed. I don't have time to look more in depth right now, but a workaround would be to have some default value for the text field and otherwise making sure that the object is never empty.

[Tonexus]

@epicfaace Ok, it looks like there is only one case of nesting that does get preserved by omitExtraData. When there is an empty object inside of an object (compared to empty array in object, empty object in array, and empty array in array), _pick still removes the inside object, but it looks like it gets readded in getDefaultFormState in utils.js.

Should the same be happening for arrays? My main concern is that once _pick is called, you lose the array, so you don't know how many array elements you need to build again, so you would have to propagate that info. The alternative would be to do something else (or in addition) when _pick is called.

[epicfaace]

It's also broken without dependencies: playground link

[MatinF]

We're seeing this issue as well in our form with the latest commit.