message: chore(Toast): using Map
diff: @@ -60,7 +60,7 @@ let allowMultiple = false;
  let currentOptions = extend({}, defaultOptions);
  // default options of specific type
  -let defaultOptionsMap: Record<string, ToastOptions | null> = {};
  +const defaultOptionsMap = new Map<string, ToastOptions>();
  function parseOptions(message: string | ToastOptions): ToastOptions {
  if (isObject(message)) {
  @@ -130,7 +130,7 @@ function Toast(options: string | ToastOptions = {}) {
  extend(
  {},
  currentOptions,
  - defaultOptionsMap[parsedOptions.type || currentOptions.type!],
  + defaultOptionsMap.get(parsedOptions.type || currentOptions.type!),
  parsedOptions
  )
  );
  @@ -164,7 +164,7 @@ function setDefaultOptions(options: ToastOptions): void;
  function setDefaultOptions(type: ToastType, options: ToastOptions): void;
  function setDefaultOptions(type: ToastType | ToastOptions, options?: any) {
  if (typeof type === 'string') {
  - defaultOptionsMap[type] = options;
  + defaultOptionsMap.set(type, options);
  } else {
  extend(currentOptions, type);
  }
  @@ -174,10 +174,10 @@ Toast.setDefaultOptions = setDefaultOptions;
  Toast.resetDefaultOptions = (type?: ToastType) => {
  if (typeof type === 'string') {
  - defaultOptionsMap[type] = null;
  + defaultOptionsMap.delete(type);
  } else {
  currentOptions = extend({}, defaultOptions);
  - defaultOptionsMap = {};
  + defaultOptionsMap.clear();
  }
  };
  