Method constructor

packages/core/src/models/select-source.ts:77–94

(workspace: IWorkspace)

  }

  constructor(workspace: IWorkspace) {
    this.workspace = workspace;
    makeObservable(this, {
      _items: observable,
      _start: observable,
      select: action,
      setStart: action,
      clear: action,
      start: computed,
      selected: computed,
      first: computed,
      firstNode: computed,
      size: computed,
      isSelected: computed,
      file: computed,
      nodes: computed,
    });
  }

  // 增加一个选中项
  add() {}