TreeNodeSchemaClass TypeAlias

Tree node schema which is implemented using a class.

Signature

/** @sealed */
export type TreeNodeSchemaClass<Name extends string = string, Kind extends NodeKind = NodeKind, TNode extends TreeNode = TreeNode, TInsertable = never, ImplicitlyConstructable extends boolean = boolean, Info = unknown, TConstructorExtra = never> = TreeNodeSchemaCore<Name, Kind, ImplicitlyConstructable, Info, TInsertable> & (undefined extends TConstructorExtra ? {
    new (data?: TInsertable | InternalTreeNode | TConstructorExtra): Unhydrated<TNode>;
} : {
    new (data: TInsertable | InternalTreeNode | TConstructorExtra): Unhydrated<TNode>;
});

Type Parameters

Parameter	Constraint	Default	Description
Name	string	string
Kind	NodeKind	NodeKind
TNode	TreeNode	TreeNode
TInsertable		never
ImplicitlyConstructable	boolean	boolean
Info		unknown
TConstructorExtra		never

Remarks

Instances of this class are nodes in the tree. This is also a constructor so that it can be subclassed.

Using classes in this way allows introducing a named type and a named value at the same time, helping keep the runtime and compile time information together and easy to refer to un a uniform way. Additionally, this works around https://github.com/microsoft/TypeScript/issues/55832 which causes similar patterns with less explicit types to infer "any" in the d.ts file.

When sub-classing a a TreeNodeSchemaClass, some extra rules must be followed:

• Only ever use a single class from the schema's class hierarchy within a document and its schema. For example, if using object(name, fields) you can do:

// Recommended "customizable" object schema pattern.
class Good extends schemaFactory.object("A", {
	exampleField: schemaFactory.number,
}) {
	public exampleCustomMethod(): void {
		this.exampleField++;
	}
}

But should avoid:

// This by itself is ok, and opts into "POJO mode".
const base = schemaFactory.object("A", {});
// This is a bad pattern since it leaves two classes in scope which derive from the same SchemaFactory defined class.
// If both get used, its an error!
class Invalid extends base {}

• Do not modify the constructor input parameter types or values:

class Invalid extends schemaFactory.object("A", {
	exampleField: schemaFactory.number,
}) {
	// This Modifies the type of the constructor input.
	// This is unsupported due to programmatic access to the constructor being used internally.
	public constructor(a: number) {
		super({ exampleField: a });
	}
}