Class Spinner

ng-dev/utils/spinner.ts:19–129

const showCursor = '\x1b[?25h';

export class Spinner {
  /** Whether the spinner is marked as completed. */
  private completed = false;
  /** The id of the interval being used to trigger frame printing. */
  private intervalId = setInterval(() => this.printFrame(), IS_CI ? 2500 : 125);
  /** The characters to iterate through to create the appearance of spinning in the spinner. */
  private spinnerCharacters = ['⠋', '⠙', '⠹', '⠸', '⠼', '⠴', '⠦', '⠧', '⠇', '⠏'];
  /** The index of the spinner character used in the frame. */
  private currentSpinnerCharacterIndex = 0;
  /** The current text of the spinner. */
  private _text: string = '';
  private set text(text: string | undefined) {
    this._text = text || this._text;
    this.printFrame(this.getNextSpinnerCharacter(), text);
  }
  private get text(): string {
    return this._text;
  }

  constructor();
  constructor(text: string);
  constructor(text?: string) {
    this.hideCursor();
    this.text = text;
  }

  /** Updates the spinner text with the provided text. */
  update(text: string) {
    this.text = text;
  }

  /** Completes the spinner marking it as successful with a `✓`. */
  success(text: string): void {
    this._complete(green('✓'), text);
  }

  /** Completes the spinner marking it as failing with an `✘`. */
  failure(text: string): void {
    this._complete(red('✘'), text);
  }

  /** Completes the spinner. */
  complete() {
    this._complete('', this.text);
  }

  /**
   * Internal implementation for completing the spinner, marking it as completed, and printing the
   * final frame.
   */
  private _complete(prefix: string, text: string) {
    if (this.completed) {
      return;
    }
    clearInterval(this.intervalId);
    this.printFrame(prefix, text);
    process.stdout.write('\n');
    this.showCursor();