Method appendToRegister

src/register/register.ts:147–188

* Appends the content at the specified index of the multicursor Register.

(
    vimState: VimState,
    register: string,
    content: RegisterContent,
    multicursorIndex: number,
  )

   * Appends the content at the specified index of the multicursor Register.
   */
  private static appendToRegister(
    vimState: VimState,
    register: string,
    content: RegisterContent,
    multicursorIndex: number,
  ): void {
    if (!Register.registers.has(register)) {
      Register.registers.set(register, []);
    }

    const contentByCursor = Register.registers.get(register)!;
    const oldContent = contentByCursor[multicursorIndex];
    if (oldContent === undefined) {
      contentByCursor[multicursorIndex] = {
        registerMode: vimState.currentRegisterMode,
        text: content,
      };
    } else {
      // Line-wise trumps other RegisterModes
      const registerMode =
        vimState.currentRegisterMode === RegisterMode.LineWise
          ? RegisterMode.LineWise
          : oldContent.registerMode;
      let newText: RegisterContent;
      if (oldContent.text instanceof RecordedState || content instanceof RecordedState) {
        newText = oldContent.text;
      } else {
        newText = oldContent.text + (registerMode === RegisterMode.LineWise ? '\n' : '') + content;
      }
      contentByCursor[multicursorIndex] = {
        registerMode,
        text: newText,
      };
    }

    if (multicursorIndex === 0 && this.isClipboardRegister(register)) {
      const newContent = contentByCursor[multicursorIndex].text;
      if (!(newContent instanceof RecordedState)) {
        void Clipboard.Copy(newContent);
      }
    }
  }

  /**
   * Updates a readonly register's content. This is the only way to do so.