_setTextEffectHandler(event) {
    const button = event.target.closest('.tui-image-editor-button');
    if (button) {
      const [styleType] = button.className.match(/(bold|italic|underline)/);
      const styleObj = {
        bold: { fontWeight: 'bold' },
        italic: { fontStyle: 'italic' },
        underline: { textDecoration: 'underline' },
      }[styleType];

      this.effect[styleType] = !this.effect[styleType];
      button.classList.toggle('active');
      this.actions.changeTextStyle(styleObj);
    }
  }
text effect set handler
@param {object} event - add button event object
@private