@gradecam/tsenum

Description
===========

Typescript supports enum now, but there are times when you may want a little more flexibility than
built-in enums give you; this package was adapted from an example in a gist linked from a typescript
issue which I cannot now find, but suffice it to say that though we have modified it a bit the idea
is not original to us.

Installing
==========

npm install --save @gradecam/tsenum

Basic Usage
===========

import {MakeEnum, TypeFromEnum} from 'tsenum';

const Colors = MakeEnum({
Red: 'red',
Blue: 'blue',
Green: 'green',
Violet: 'violet',
Black: 'black'
});
type Colors = TypeFromEnum;

// type Colors = 'red' | 'blue' | 'green' | 'violet' | 'black'
// value Colors is a frozen object with the keys expected
// typeof Colors.Red is 'red', et al

carColor: Colors = 'red'; // valid
carColor = Colors.Green; // valid
carColor = 'yellow'; // typescript error, not a valid color

Combining types
===============

MakeEnum will merge multiple enum objects into one (up to 9), allowing you to combine types.

import {MakeEnum, TypeFromEnum} from 'tsenum';

const PrimaryColors = MakeEnum({
Red: 'red',
Blue: 'blue',
Green: 'green',
});
type PrimaryColors = TypeFromEnum;

const SecondaryColors = MakeEnum({
Yellow: 'yellow',
Cyan: 'cyan',
Magenta: 'magenta'
});
type SecondaryColors = TypeFromEnum;

const AllColors = MakeEnum(PrimaryColors, SecondaryColors);
type AllColors = TypeFromEnum;
// type AllColors = 'red' | 'blue' | 'green' | 'yellow' | 'cyan' | 'magenta'

Getting an array of possible values
===================================

Sometimes you may want an array of possible values, such as when defining an enum type in a mongoose
schema. Since the enum is an object, you can use Object.values to get that:

import {MakeEnum, TypeFromEnum} from 'tsenum';

const PrimaryColors = MakeEnum({
Red: 'red',
Blue: 'blue',
Green: 'green',
});
type PrimaryColors = TypeFromEnum;

const PrimaryColorList = Object.values(PrimaryColors); // ['red', 'blue', 'green']
// typeof PrimaryColorList = Array<'red'|'blue'|'green'>

Allowed value types
===================

Currently you can use any string, number, or boolean as a value