A JavaScript library that helps with the enum pattern. Also supports TypeScript.
Installation:
npm install enumify
class Color extends Enumify { static red = new Color(); static orange = new Color(); static yellow = new Color(); static green = new Color(); static blue = new Color(); static purple = new Color(); static _ = this.closeEnum(); // TypeScript: Color.closeEnum() } // Instance properties assert.equal( Color.red.enumKey, 'red'); assert.equal( Color.red.enumOrdinal, 0); // Prototype methods assert.equal( 'Color: ' + Color.red, // .toString() 'Color: Color.red'); // Static `.enumKeys` and static `.enumValues` assert.deepEqual( Color.enumKeys, ['red', 'orange', 'yellow', 'green', 'blue', 'purple']); assert.deepEqual( Color.enumValues, [ Color.red, Color.orange, Color.yellow, Color.green, Color.blue, Color.purple ]); // Static `.enumValueOf()` assert.equal( Color.enumValueOf('yellow'), Color.yellow); // Iterability const result = []; const iterated = [...Color]; for (const c of Color) { result.push('Color: ' + c); } assert.deepEqual( iterated, [ Color.red, Color.orange, Color.yellow, Color.green, Color.blue, Color.purple, ]);
See:
ts/test/index_test.tsts/test/state.ts
Run tests like this (after compiling TypeScript, e.g. via npm run build):
npm t dist/test/index_test.js
The enum pattern and Enumify are based on public static fields. Support for them currently looks as follows:
- MDN lists support for public static fields in various JavaScript engines.
- Babel has the plugin
plugin-proposal-class-propertiesfor public static fields. - TypeScript has supported static fields in classes for a very long time.