why would we use enum in javascript code example

Example: javascript enum

const seasons = {
  SUMMER: {
    BEGINNING: "summer.beginning",
    ENDING: "summer.ending"
  },
  WINTER: "winter",
  SPRING: "spring",
  AUTUMN: "autumn"
};

let season = seasons.SUMMER.BEGINNING;

if (!season) {
  throw new Error("Season is not defined");
}

switch (season) {
  case seasons.SUMMER.BEGINNING:
  // Do something for summer beginning
  case seasons.SUMMER.ENDING:
  // Do something for summer ending
  case seasons.SUMMER:
  // This will work if season = seasons.SUMMER
  // Do something for summer (generic)
  case seasons.WINTER:
  //Do something for winter
  case seasons.SPRING:
  //Do something for spring
  case seasons.AUTUMN:
  //Do something for autumn
}