How to use the @material/select.MDCSelectFoundation.strings function in @material/select

notifyChange: () => {
        this.emit(MDCSelectFoundation.strings.CHANGE_EVENT, this);

        if (this.ngModelCtrl_) {
          this.ngModelCtrl_.$setViewValue(this.value);
        }
      },
      getWindowInnerHeight: () => this.$window.innerHeight,

setValue: (value: string) => {
        if (this.menuElement) {
          const element = this.menuElement.querySelector(
            `[${MDCSelectFoundation.strings.ENHANCED_VALUE_ATTR}="${value}"]`
          );

          const selectedIndex =
            element && this.menu
              ? this.menu.items.indexOf(element as HTMLLIElement)
              : -1;
          const selectedItem = this.menu && this.menu.items[selectedIndex];

          let selectedTextContent = '';

          if (!!selectedItem) {
            selectedTextContent =
              selectedItem.dataset['label'] ||
              ((selectedItem.textContent && selectedItem.textContent.trim()) ||
                '');
          }

initialize(menuFactory = (el) => new MDCMenu(el), labelFactory = (el) => new MDCSelectLabel(el)) {
    this.surface_ = this.root_.querySelector(MDCSelectFoundation.strings.SURFACE_SELECTOR);
    const labelElement = this.root_.querySelector(MDCSelectFoundation.strings.LABEL_SELECTOR);
    if (labelElement) {
      this.label_ = labelFactory(labelElement);
    }
    this.bottomLine_ = this.root_.querySelector(MDCSelectFoundation.strings.BOTTOM_LINE_SELECTOR);
    this.selectedText_ = this.root_.querySelector(MDCSelectFoundation.strings.SELECTED_TEXT_SELECTOR);
    this.menuEl_ = this.root_.querySelector(MDCSelectFoundation.strings.MENU_SELECTOR);
    this.menu_ = menuFactory(this.menuEl_);
  }

getValue: () => {
        let value = '';
        const listItem: any =
          this.menu && this.menu.items[this.state.selectedIndex];
        if (
          listItem &&
          listItem.hasAttribute(MDCSelectFoundation.strings.ENHANCED_VALUE_ATTR)
        ) {
          value = listItem.getAttribute(
            MDCSelectFoundation.strings.ENHANCED_VALUE_ATTR
          );
        }
        return value === '' && this.props.placeholder ? ' ' : value;
      },
      setValue: (value: string) => {