Add MultiEnum renderer for enums and oneOf

[AlexandraBuzila]

Render an anyOf array of consts as a list of checkboxes. The checkbox is
checked if the array item it represents is present in the data.

[coveralls]

Coverage increased (+0.005%) to 88.587% when pulling 99fed1d on AlexandraBuzila:enum-array into 7800718 on eclipsesource:master.

[sdirix]

In general I like it very much. However there are some things I would like to see differently.

Currently the schema tested for looks like this

"property": {
  "type": "array",
  "items": {
    "anyOf": [
      { },
    ]
  },
},

which doesn't really fit to the use case:

• The schema allows the same entry multiple times, but our control only handles them uniquely (the control therefore misbehaves if the same entry is there multiple times)
• anyOf stands for that at least one item matches. However we're handling it like "enums", which are unique. So it should be oneOf.
• To be consistent with our other oneOfEnum controls we should check whether the items are oneOf and contain a const in each entry.
• Ideally we should also be able to handle enum content

I would prefer to support the following schemas:

"property": {
  "type": "array",
  "items": {
    "oneOf": [
      {
        "const": <any>,
        "title": "mylabel"
      },
      {
        "const": <any>,
        "title": "otherLabel"
      },
    ]
  },
  "uniqueItems": true
},

and

"property": {
  "type": "array",
  "items": {
    "type": "string",
    "enum": ["a", "b", "c"]
  },
  "uniqueItems": true
},

So we check for

• type array with unique items
• the items are either enum or oneOf containing const

---

Please also add an example to the example app.

[sdirix]

To be consistent with other controls we should default export the wrapped version

[sdirix]

Don't wrap here, but use the already wrapped imported version

[sdirix]

Careful: The value of const can be anything! It doesn't need to be a string, but could for example be an object, array, etc. Please see mapStateToOneOfEnumProps where we already had to handle the case.

[sdirix]

If you would use withJsonFormsArrayControlProps you would get functions to add and remove items to the array for free, i.e. addItem, removeItems, moveUp and moveDown would get injected. schema would also already point to the items object. Actually that doesn't make so much sense as these functions are index based, which is not really the use case here.

[sdirix]

Additionally it would be great to extract all the logic from the renderer. I would prefer a new mapStateToMultiEnumProps and mapDispatchToMultiEnumProps combined into a React withJsonFormsMultiEnumProps.

• mapStateToMultiEnumProps: extracting the items options from oneOf or enum, similar to mapStateToEnumPros and mapStateToOneOfEnumProps
• mapDispatchToMultiEnumProps: providing a addItem and removeItem function which can be used for toggling. Using this we can also remove the useRef workaround

By extracting the logic from the renderer we can easily write a multi-select enum with a different renderer (e.g. Material UI's multi select dropdown) as well as more easily add the same renderer in the other renderer sets too.

[AlexandraBuzila]

I updated the commit to include you comments, Stefan. The renderer now supports both oneOf and enum items.

[sdirix]

Looks good!

[sdirix]

We should respect empty titles ;)

Suggested change

	e.title || (typeof e.const === 'string' ? e.const : JSON.stringify(e.const))
	e.title ?? (typeof e.const === 'string' ? e.const : JSON.stringify(e.const))