How to Print An Enum's Properties in JavaScript

JavaScript doesn't support enums natively, but you can use POJOs to simulate vanilla JavaScript enums as shown below.

function createEnum(values) {
  const enumObject = {};
  for (const val of values) {
    enumObject[val] = val;
  }
  return Object.freeze(enumObject);
}

// { Up: 'Up', Down: 'Down', Left: 'Left', Right: 'Right' }
createEnum(['Up', 'Down', 'Left', 'Right']);

Using toString() on an Enum

Since an enum is just an object, toString() doesn't print the actual contents of the enum.

createEnum(['Up', 'Down', 'Left', 'Right']).toString(); // '[object Object]'

You should use Object.keys() instead, which returns an array of strings containing each of the enum property names.

Object.keys(createEnum(['Up', 'Down', 'Left', 'Right'])); // ['Up', 'Down', 'Left', 'Right']

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