Question

I have an enum in a file:

goog.provide('animals.Fish');

animals.Fish = function(obj) {
  this.name_ = obj[animals.Fish.Properties.NAME];
  this.awesomenessLevel_ = obj[animals.Fish.Properties.AWESOMENESS];
}

/**
 * Public list of properties.
 * @enum {string}
 */
animals.Fish.Properties = {
  NAME: 'name',
  AWESOMENESS: 'awesomenessLevel',
}

How come I can’t access this enum as a static field of Fish in another class like this?

goog.require('animals.Fish');
...
var tuna = new animals.Fish(
  animals.Fish.NAME: 'tuna',
  animals.Fish.AWESOMENESS: '100'
)
...

Answer 1

Closure enumeration types are based on the concept of Enum Types from languages such as Java and C++. In Java, enum types are defined as follows:

An enum type is a type whose fields consist of a fixed set of constants. Common examples include compass directions (values of NORTH, SOUTH, EAST, and WEST) and the days of the week.

In your example above, animals.Fish.Properties should probably be represented as a record type, since the assigned values are not constants. In the example below, animals.Fish.Properties has been renamed animals.Properties so that it could be applied to any type of animal (not just fish).

fish.js

goog.provide('animals.Fish');
goog.provide('animals.Properties');


/** @typedef {{name: string, awesomeness: string}} */
animals.Properties;


/**
 * @param {animals.Properties} properties Animal properties.
 * @constructor 
 */
animals.Fish = function(properties) {
  /** @type {string} */
  this.name_ = properties.name;

  /** @type {string} */
  this.awesomenessLevel_ = properties.awesomeness;
};


/**
 * @return {string} The name of the fish.
 */
animals.Fish.prototype.getName = function() {
  return this.name_;
};

animals_app.js

goog.provide('animals.app');

goog.require('animals.Fish');

animals.app.tuna = new animals.Fish({name: 'tuna', awesomeness: '100'});    
alert(animals.app.tuna.getName()); // alerts 'tuna'

On a side note, in the original example there should not be a comma after: AWESOMENESS: 'awesomenessLevel' in the definition of animals.Fish.Properties. In addition, in your second file you need to use the fully qualified enum name. So instead of animals.Fish.NAME it would be animals.Fish.Properties.NAME.