Enumerations

JavaScript getter syntax offers an alternative to using switch to dispatch or route functions with zero parameters:

const TrafficLight = {
  get red() {
    return "red"; 
  },
  get yellow() {
    return "yellow";
  },
  "green: "green"
};

Then TrafficLight["red"] returns "red". In this simple example, it’s just a more convoluted way of getting a string keyword to return itself, which can be turn in a more conventional ways as in the “green” example, but illustrates an ellegant way to use methods in object literals.

A workaround for no paramter passing to getters is to have them share scope with the required data. They can also mutate an object they share scope with.

describe("Module Scope", function() {
  const myObj = {};
  const myEnum = {
    get red() {
      myObj.color = "red";
    },
    get yellow() {
      myObj.color = "yellow";
    },
    get green() {
       myObj.color = "green";
    }
  };
  it ('myEnum["red"] should mutate myObj.color to "red"', function() {
    myEnum["red"];
    expect(myObj.color).toBe("red");
  });
});