make `fields` accept options such as `name`, `type`, and `options`

For example

```js
{
myEnumField: {name:"My Enum Field",options:["option 1", "option 2"]},
myDateField: {name:"My Date Field",type:"date"},
}
```

The issue gives a JavaScript example for configuring fields with name, type, and options. Locate the existing fields implementation and its tests, then verify that the shown enum and date configurations are accepted and covered by tests.

Rédigé par le modèle d'indexation à partir du texte de l'issue.