website/playground/Playground.js/Playground/handleOptionValueChange
class Playground:  handleOptionValueChange(option, value) {
    this.setState((state) => {
      const options = { ...state.options };

      if (option.type === "int" && Number.isNaN(value)) {
        delete options[option.name];
      } else {
        options[option.name] = value;
      }

      const content =
        state.content === "" ||
        state.content === getCodeSample(state.options.parser)
          ? getCodeSample(options.parser)
          : state.content;

      return { options, content };
    });
  }