@cedx/enum

Enums for JS

Yet another implementation of enumerated types for JavaScript.

This implementation does not try to reproduce the semantics of traditional enumerations, like the ones found in C# or Java languages. It just gives a set of static methods to ease working with the values of an object literal representing an enumerated type.

Requirements

The latest Node.js and npm versions. If you plan to play with the sources, you will also need the latest Gulp version.

Installing via npm

From a command prompt, run:

$ npm install --save @cedx/enum

Usage

Create the enumeration

Just use the Enum.create() method with an object literal containing scalar values (e.g. only booleans, numbers and strings):

const {Enum} = require('@cedx/enum');

/**
 * Specifies the day of the week.
 * @type {object}
 */
const DayOfWeek = Enum.create({
  sunday: 0,
  monday: 1,
  tuesday: 2,
  wednesday: 3,
  thursday: 4,
  friday: 5,
  saturday: 6
});

The Enum.create() method creates an anonymous class from the specified object. This class has the same values as the provided object, and some additional helper methods.

The created class has a constructor throwing a TypeError: it prohibits its instantiation. This class is also freezed to prevent any attempt at modifying its shape.

Work with the enumeration

Check whether a value is defined among the enumerated type:

DayOfWeek.isDefined(DayOfWeek.sunday); // true
DayOfWeek.isDefined('foo'); // false

Ensure that a value is defined among the enumerated type:

DayOfWeek.assert(DayOfWeek.monday); // DayOfWeek.monday
DayOfWeek.assert('foo'); // (throws TypeError)

DayOfWeek.coerce(DayOfWeek.monday); // DayOfWeek.monday
DayOfWeek.coerce('bar'); // null
DayOfWeek.coerce('baz', DayOfWeek.tuesday); // DayOfWeek.tuesday

Get the zero-based position of a value in the enumerated type declaration:

DayOfWeek.getIndex(DayOfWeek.wednesday); // 3
DayOfWeek.getIndex('foo'); // -1

Get the name associated to an enumerated value:

DayOfWeek.getName(DayOfWeek.thursday); // "thursday"
DayOfWeek.getName('foo'); // "" (empty)

Get information about the enumerated type:

DayOfWeek.getEntries();
// [["sunday", 0], ["monday", 1], ["tuesday", 2], ["wednesday", 3], ["thursday", 4], ["friday", 5], ["saturday", 6]]

DayOfWeek.getNames();
// ["sunday", "monday", "tuesday", "wednesday", "thursday", "friday", "saturday"]

DayOfWeek.getValues();
// [0, 1, 2, 3, 4, 5, 6]

See also

• API reference
• Code coverage
• Continuous integration

License

Enums for JS is distributed under the MIT License.

Changelog

Version 3.2.0

• Added support for browser testing.
• Updated the package dependencies.