Method onCMUpdate

src/core/nodeviews/code-block.ts:1524–1547

* CodeMirror 更新回调

(update: ViewUpdate)

   * CodeMirror 更新回调
   */
  private onCMUpdate(update: ViewUpdate): void {
    if (this.updating) return;

    if (update.docChanged) {
      const pos = this.getPos();
      if (pos === undefined) return;

      const newText = update.state.doc.toString();

      // 更新 ProseMirror 文档
      const tr = this.view.state.tr;
      const start = pos + 1;
      const end = pos + 1 + this.node.content.size;

      tr.replaceWith(start, end, newText ? this.view.state.schema.text(newText) : []);

      this.view.dispatch(tr);

      // 更新 Mermaid 预览
      if (this.node.attrs.language === "mermaid") {
        this.createMermaidPreview(newText);
      }
    }
  }

  /**
   * 转发选区到 ProseMirror