Fields Properties

Every field exposes editable props (set during definition, mutable at runtime) and computed props (read-only values derived from field state).

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Editable Props

Props you can define when creating fields and modify at runtime via field.set(prop, value).

Value & Display

Property	Type	Default	Description
type	string	"text"	HTML input type (text, email, checkbox, file, number, etc.)
value	any	undefined	Current field value
initial	any	undefined	Initial value on mount
default	any	undefined	Value used when reset() is called
label	string	""	Human-readable field label
placeholder	string	""	Placeholder text for the input
extra	any	null	Arbitrary metadata (useful for select options, custom data)

Input Behavior

Property	Type	Default	Description
disabled	boolean	false	Field disabled state
deleted	boolean	false	Soft-deleted state (requires softDelete option)
nullable	boolean	false	Allow null as a field value
autoFocus	boolean	false	Focus this field on form initialization
inputMode	string	undefined	Mobile keyboard mode: none, text, decimal, numeric, tel, search, email, url
autoComplete	string	undefined	HTML autocomplete attribute
ref	React Ref	undefined	React ref, populated automatically when bind() is used

Validation

Property	Type	Default	Description
rules	string	null	DVR validation rules (e.g. "required|email|min:6")
validators	array	null	VJF validation functions
validatedWith	string	"value"	Field prop to validate instead of value (see validatedValue)
related	string[]	[]	Other field paths to re-validate when this field changes

Converters & Computed

Property	Type	Default	Description
converter	function	identity	Function controlling the value computed prop output
converters	function[]	-	Array of converter functions
input	function	identity	Input converter: maps user input to stored value
output	function	identity	Output converter: maps stored value to output
computed	function	undefined	Dynamic value function: ({ form, field }) => value

Bindings & Options

Property	Type	Default	Description
bindings	string	"default"	Key of the registered binding template/rewriter to use
options	object	{}	Per-field Form Options, with fallback on global options
class	class	undefined	Custom Field class (unified mode only, must extend Form.Field)
classes	object	undefined	Custom Field classes keyed by field path (separated mode only)

Events & MobX

Property	Type	Default	Description
hooks	object	{}	Event hook functions
handlers	object	{}	Event handler functions
observers	array	null	MobX observers on field props or fields map. Auto-loaded for dynamic arrays.
interceptors	array	null	MobX interceptors on field props or fields map. Auto-loaded for dynamic arrays.

Nested

Property	Type	Default	Description
fields	array	undefined	Nested sub-field definitions
name	string	key	Overrides the object key as field name (array syntax)

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Computed Props

Read-only properties derived from the field state. Accessible at runtime (e.g. field.isValid, field.error).

Validation State

Property	Type	MobX	Description
isValid	boolean	computed	true if the field and all nested fields pass validation
hasError	boolean	computed	true if the field or any nested field has errors
error	string	computed	First error message (null if no error, null when showError is false)
errorSync	string	observable	Synchronous error message
errorAsync	string	observable	Asynchronous error message (from async validation)
validating	boolean	computed	true while validation is in progress
validated	int	computed	Number of times the field has been validated

Identity & Structure

Property	Type	MobX	Description
key	string	-	Field key (same as name if not provided)
name	string	-	Field name (same as key if not provided)
path	string	-	Full field path (dot-notated for nested fields, e.g. "address.city")
size	int	computed	Number of child fields (0 for leaf fields)
id	string	-	Unique field ID (generated by uniqueId option)
hasNestedFields	boolean	computed	true if the field contains nested sub-fields
hasIncrementalKeys	boolean	computed	true if nested fields use incremental numeric keys

State & Interaction

Property	Type	MobX	Description
focused	boolean	computed	true if the field is currently focused
blurred	boolean	computed	true if the field has lost focus at least once
touched	boolean	computed	true if the field has been focused at least once
changed	int	computed	Number of times the field value has changed
submitting	boolean	computed	true while the form/fieldset is submitting
submitted	int	computed	Number of times the fieldset has been submitted
actionRunning	boolean	computed	true while a clear, reset, or submit action is in progress (useful for loading spinners)
resetting	boolean	observable	true while the field is being reset
clearing	boolean	observable	true while the field is being cleared

Value Comparison

Property	Type	MobX	Description
isDirty	boolean	computed	true if the current value differs from the initial value
isPristine	boolean	computed	true if the current value equals the initial value
isDefault	boolean	computed	true if the current value equals the default value
isEmpty	boolean	computed	true if the field value is empty (delegates to child fields for nested fields)

Special

Property	Type	MobX	Description
checked	any	computed	Current value when type is "checkbox"; undefined otherwise
validatedValue	any	computed	Value of the field prop specified by validatedWith (default: "value")
files	any	observable	File data populated by onDrop event handler for type: "file" fields
showError	boolean	observable	Controls whether error messages are visible
validationErrorStack	string[]	observable	Stack of validation error messages

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Occurrence Strategy

Some computed props use different aggregation strategies when checking nested fields:

Property	Strategy	Meaning
isValid, isPristine, isDefault, isEmpty	every	Must be true for ALL nested fields
hasError, isDirty, focused, blurred, touched	some	true if ANY nested field is true