feat(json-crdt): 🎸 add Model.create() method

src/json-crdt-extensions/peritext/Peritext.ts

@@ -53,12 +53,10 @@ export class Peritext implements Printable {
   ) {
     this.savedSlices = new Slices(this.model, slices, this.str);
 
-    const extraModel = Model.withLogicalClock(SESSION.GLOBAL)
-      .setSchema(s.vec(s.arr([])))
-      .fork(this.model.clock.sid + 1);
+    const extraModel = Model.create(s.vec(s.arr([])), this.model.clock.sid - 1);
     this.extraSlices = new Slices(extraModel, extraModel.root.node().get(0)!, this.str);
 
-    const localModel = Model.withLogicalClock(SESSION.LOCAL).setSchema(s.vec(s.arr([])));
+    const localModel = Model.create(s.vec(s.arr([])), SESSION.LOCAL);
     const localApi = localModel.api;
     localApi.onLocalChange.listen(() => {
       localApi.flush();

src/json-crdt/model/Model.ts

@@ -55,6 +55,20 @@ export class Model<N extends JsonNode = JsonNode<any>> implements Printable {
     return new Model(clockVector);
   }
 
+  /**
+   * Create a new strictly typed JSON CRDT model.
+   *
+   * @param schema The schema (typing and default value) to set for this model.
+   * @param sid Session ID to use for local operations. Defaults to a random
+   *            session ID.
+   * @returns A strictly typed model.
+   */
+  public static create<S extends NodeBuilder>(schema?: S, sid: number = randomSessionId()): Model<SchemaToJsonNode<S>> {
+    const model = Model.withLogicalClock(sid) as unknown as Model<SchemaToJsonNode<S>>;
+    if (schema) model.setSchema(schema, true);
+    return model as Model<SchemaToJsonNode<S>>;
+  }
+
   /**
    * Un-serializes a model from "binary" structural encoding.
    * @param data Binary blob of a model encoded using "binary" structural