stein197 / js-enum

Complex enum implementation for TypeScript

Complex enum implementation for JavaScript & TypeScript

Installation

npm install @stein197/enum

Motivation

TypeScript provides a very simple and primitive implementation of enumerations. All you can do with native implementation is to declare numeric or string enum values. But sometimes there is a need of more complex enumerations - that have properties or even methods. This package provides such an implementation that exists in Java and PHP.

Usage

The package provides only one simple class Enum that all complex enums must extend from. Assume that there is an enum Status which represents HTTP statuses. Status can have status code and a message. In TypeScript it could be reached by creating two distinct enums. Instead, use complex enumerations like this:

import Enum from "@stein197/enum";

class Status extends Enum {

	public static readonly Ok = new Status(200, "Ok");
	public static readonly NotFound = new Status(404, "Not found");
	public static readonly InternalServerError = new Status(500, "Internal server error");

	public constructor(public readonly code: number, public readonly message: string) {}

	// Since it's a regular class, methods can be used as well
	public getMessage(): string {
		return this.message;
	}
}

// Unique properties
Status.NotFound.name; // "NOT_FOUND"

// Custom properties and methods
Status.Ok.message; // "Ok"
Status.Ok.getMessage(); // "Ok"

// Retrieving arbitrary data
Status.values(); // [Status.Ok, Status.NotFound, Status.InternalServerError]
Status.from("NotFound"); // By name: Status.NotFound
Status.from("Nonexistent"); // null

NPM scripts

• clean Cleans compiled files
• build, build:dev Builds the project
• test Runs all unit tests