Javascript：如何從媒體類型數組呈現先前的斷點。function getCurrentBreakpoint(mediaType) {  const mediaTypes = ["xs", "sm", "md", "lg", "xl", "infinity"];  //suppose current mediaType is `infinity`   // I have to return mediaType as `xl` . always one prevoius state from the current.}目前可以通過使用來實現if ... else or by switch case let breakpoint;  switch (mediaType) {    case "infinity":      breakpoint = "xl";      break;    case "xl":      breakpoint = "lg";      break;    case "lg":      breakpoint = "md";      break;    case "md":      breakpoint = "sm";      break;    default:      breakpoint = "xs";  }