Constants Configuration

A collection of unique Symbol identifiers used globally by the Ignition engine to differentiate between raw data and engine-level metadata.

Core Symbols

Name	Type	Description
METADATA	Symbol	The internal key used to store engine-specific data within proxies.
PLACEHOLDER	Symbol	A unique marker used to represent nil values in reactive tables or uninitialized fields.

Member Flags

These flags are passed into property or func descriptors to modify their behavior during the Linker phase.

Flag	Type	Description
Optional	Symbol	Marks a property as not required during the instantiation check.
Static	Symbol	Binds the member to the Class Interface rather than the object instance.
Constant	Symbol	Prevents the value from being changed after the class is finalized.
Virtual	Symbol	Explicitly allows a member to be overwritten by a mixin or a child class via extends.
Readonly	Symbol	Prevents writing to the property from outside the class constructor.
Reactive	Symbol	Forces the property to be wrapped in a Value object for dependency tracking.