feat(json-crdt): 🎸 add abstract ExtNode class

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

@@ -1,18 +1,9 @@
-import {printTree} from 'tree-dump/lib/printTree';
 import {MNEMONIC} from './constants';
-import type {ITimestampStruct} from '../../json-crdt-patch/clock';
-import type {ExtensionJsonNode, JsonNode} from '../../json-crdt';
-import type {Printable} from 'tree-dump/lib/types';
+import {ExtNode} from '../../json-crdt/extensions/ExtNode';;
 import type {PeritextDataNode} from './types';
 
-export class PeritextNode implements ExtensionJsonNode, Printable {
-  public readonly id: ITimestampStruct;
-
-  constructor(public readonly data: PeritextDataNode) {
-    this.id = data.id;
-  }
-
-  // -------------------------------------------------------- ExtensionJsonNode
+export class PeritextNode extends ExtNode<PeritextDataNode> {
+  // ------------------------------------------------------------------ ExtNode
 
   public name(): string {
     return MNEMONIC;
@@ -22,22 +13,4 @@ export class PeritextNode implements ExtensionJsonNode, Printable {
     const str = this.data.get(0)!;
     return str.view();
   }
-
-  public children(callback: (node: JsonNode) => void): void {}
-
-  public child?(): PeritextDataNode {
-    return this.data;
-  }
-
-  public container(): JsonNode | undefined {
-    return this.data.container();
-  }
-
-  public api: undefined | unknown = undefined;
-
-  // ---------------------------------------------------------------- Printable
-
-  public toString(tab?: string): string {
-    return this.name() + printTree(tab, [(tab) => this.data.toString(tab)]);
-  }
 }

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

@@ -9,6 +9,7 @@ import type {ExtensionDefinition} from '../../json-crdt';
 export const PeritextExt: ExtensionDefinition<PeritextDataNode, PeritextNode, PeritextApi> = {
   id: ExtensionId.peritext,
   name: MNEMONIC,
+  // TODO: Simplify to `BUILD_SCHEMA(text)`.
   new: (text: string) => ext(ExtensionId.peritext, BUILD_SCHEMA(text)),
   Node: PeritextNode,
   Api: PeritextApi,

src/json-crdt/extensions/ExtNode.ts

@@ -0,0 +1,35 @@
+import {printTree} from 'tree-dump/lib/printTree';
+import type {ITimestampStruct} from '../../json-crdt-patch/clock';
+import type {ExtensionJsonNode, JsonNode} from '..';
+import type {Printable} from 'tree-dump/lib/types';
+
+export abstract class ExtNode<N extends JsonNode> implements ExtensionJsonNode, Printable {
+  public readonly id: ITimestampStruct;
+
+  constructor(public readonly data: N) {
+    this.id = data.id;
+  }
+
+  // -------------------------------------------------------- ExtensionJsonNode
+
+  public abstract name(): string;
+  public abstract view(): unknown;
+
+  public children(callback: (node: JsonNode) => void): void {}
+
+  public child?(): N {
+    return this.data;
+  }
+
+  public container(): JsonNode | undefined {
+    return this.data.container();
+  }
+
+  public api: undefined | unknown = undefined;
+
+  // ---------------------------------------------------------------- Printable
+
+  public toString(tab?: string): string {
+    return this.name() + printTree(tab, [(tab) => this.data.toString(tab)]);
+  }
+}