enumtype v0.0.1

Enum Type for ECMAScript

This enum type implementation focuses on elegance of code, avoids unnecessary features and ambiguity. Thus things like nested enum will never be implemented.

Installation

npm i -S enumtype

Usage

Enum definition and access

const EnumType = require('enumtype');

const MyAccessType = EnumType.define([
    'READ',
    'WRITE',
    'READWRITE'
]);

let accessType = MyAccessType.READ;
let invalidAccessType = MyAccessType.EXECUTE; // This will throw RangeError

// Print all element names
for (let name in MyAccessType) {
    console.log(name);
}

Validation

const EnumType = require('enumtype');
const MyEnum = EnumType.define(['ONE', 'TWO']);

// Verify if an object is an enum
console.log('The right way to verify enum object: ', MyEnum instanceof EnumType);

// Use in operator to validate both enum labels and values
console.log('Label check:', 'ONE' in MyEnum); // true
let oneValue = MyEnum.ONE;
console.log('Value check:', oneValue in MyEnum); // true

// Elements from different definitions are not equal
const MyEnum2 = EnumType.define(['ONE', 'TWO']);
console.log('Are two similar enum definitions equal?', MyEnum.ONE === MyEnum2.ONE); // false

Serialization

// Don't use JSON.stringify to get JSON representation of enum
console.log('JSON of MyEnum', EnumType.toJson(MyEnum));

Caveats

enumtype uses Proxy to enforce valid element access by throwing error when an undefined element is accessed. On the other hand JSON.stringify implementation of current NodeJS (last checked on v8.x) seems to check the existence of toJSON method by actually accessing it, not using something like in operator. Therefore calling JSON.stringifydirectly on enumtype object will throw an error.