How to use the @material/drawer.MDCTemporaryDrawerFoundation.strings function in @material/drawer

mounted () {
    const {FOCUSABLE_ELEMENTS, OPACITY_VAR_NAME} = MDCTemporaryDrawerFoundation.strings;

    let vm = this;
    this.foundation = new MDCTemporaryDrawerFoundation({
      addClass (className) {
        vm.$set(vm.classes, className, true);
      },
      removeClass (className) {
        vm.$delete(vm.classes, className);
      },
      hasClass (className) {
        return Boolean(vm.classes[className]) || (vm.$el && vm.$el.classList.contains(className));
      },
      hasNecessaryDom () {
        return Boolean(vm.$refs.drawer);
      },
      registerInteractionHandler (evt, handler) {

updateCssVariable: (value: string) => {
                if (util.supportsCssCustomProperties())
                    this._elm.nativeElement.style.setProperty(MDCTemporaryDrawerFoundation.strings.OPACITY_VAR_NAME, value);
            },
            eventTargetHasClass: (target: HTMLElement, className: string) => {