DecimalRangeField

Async choices for this field.

This can be used with SelectAsyncChoicesWidget or useAsyncChoices to retrieve the choices.

Is this field required when saving a record?

This isn't currently used by anything in PrestoJS but is useful if you are creating generic validators for form values.

If true an empty string value should be converted to a null value

This isn't currently used by anything inPrestoJS but is useful if you are writing generic data transformations (eg. transforming a form submission to send to the server) and need to know whether a value should be forced to null.

When accessed on a bound field will return the current instance of the ViewModel the field is bound to.

If called on an unbound field then this will always be undefined and a warning will be raised.

The choices defined for this field (if any).

When constructing the field you can pass in choices as either a Map of value to label or an array of 2-tuples being the value and label for that value. When retrieved from the field these are always returned as a Map.

Get the default value for this field.

Any props for components that use this field that were passed through to the Field. Don't access this directly - call getFormatterProps instead.

Help text that can be displayed with the form widget

This rendered by FormItem under the field widget.

Returns true if field is bound to a ViewModel instance. When a field is bound to a instance the value for that field is accessible on the 'value' property.

Label that can be displayed as the form label for a widget

If not specified will be generated from name.

This is rendered by FormItem as the label for a form input.

The ViewModel class this field is attached to.

This will throw an error if the field is not attached to a model.

The name of this field.

This is set automatically when the ViewModel is created based on the object key the field was set on:

// The field here will get a `name` of `id` as that matches the key in the object.
viewModelFactory({ id: new Field() }, { pkFieldName: "id" })

This will throw an error if the field is not attached to a model.

Indicates this field should only be read, not written. Not enforced but can be used by components to adjust their output accordingly (eg. exclude it from a form or show it on a form with a read only input)

When isBound is true this will return the current value of this field on the bound ViewModel otherwise it will always be undefined. You can get the bound field using the _f property on the ViewModel.

Most of the time you would get the value for a field directly from the record:

const User = viewModelFactory(
  { id: new Field(), name: new Field() },
  { pkFieldName: "id" }
)
const user = new User({ id: 1, name: "Jo" })
user.name === "Jo"
// true

But if you want to pass the field itself along with the value this is useful (eg. see FieldFormatter):

// FieldFormatter now has access to the `Field` instance and the value
;<FieldFormatter field={user._f.name} />

Any props for components that use this field that were passed through to the Field. Don't access this directly - call getWidgetProps instead.

Indicates this field should only be written only and is not intended to be read directly. This is not enforced but can be used by components to adjust their output accordingly (eg. exclude it from a detail view on a record)

Field class name

This exists so getWidgetForField and getFormatterForField can select the widget or formatter for a field without needing to import all fields up front. For example the following example avoids importing any code upfront that isn't needed which wouldn't be possible if using instanceof.

if (field.fieldClassName === "ImageField") {
  return React.lazy(
    () => import("./components/ImageWidget")
  )
}

For custom fields this isn't required unless your implementation of getWidgetForField wants to avoid importing the field up front.