feat(json-crdt): 🎸 start Extension implementation

src/json-crdt/extensions/Extension.ts

@@ -0,0 +1,24 @@
+import {s, type NodeBuilder, type nodes} from "../../json-crdt-patch";
+import type {ModelApi} from "../model";
+import type {JsonNode} from "../nodes";
+import type {ExtensionApi, ExtensionJsonNode} from "./types";
+
+export class Extension<
+  Id extends number,
+  Node extends JsonNode,
+  ENode extends ExtensionJsonNode,
+  EApi extends ExtensionApi<ENode>,
+  ESchema extends NodeBuilder,
+> {
+  constructor(
+    public readonly id: Id,
+    public readonly name: string,
+    public readonly schema: (...args: any[]) => ESchema,
+    public readonly Node: new (data: Node) => ENode,
+    public readonly Api: new (node: ENode, api: ModelApi) => EApi,
+  ) {}
+
+  public new(...args: any[]): nodes.ext<Id, ESchema> {
+    return s.ext<Id, ESchema>(this.id, this.schema(...args));
+  }
+}

src/json-crdt/extensions/types.ts

@@ -13,10 +13,11 @@ export interface ExtensionDefinition<
   Node extends JsonNode = JsonNode,
   ENode extends ExtensionJsonNode = ExtensionJsonNode,
   EApi extends ExtensionApi<ENode> = ExtensionApi<ENode>,
+  ESchema extends NodeBuilder = NodeBuilder,
 > {
   id: number;
   name: string;
-  new: (...args: any[]) => NodeBuilder;
+  new: (...args: any[]) => ESchema;
   Node: new (data: Node) => ENode;
   Api: new (node: ENode, api: ModelApi) => EApi;
 }