SparK-Cruz/enum-mixin

Enum() mixin

Package enum-mixin

Enum mixin for declaring "Java-like" enums.

Usage

Class statement:

class Fruit extends Enum() {
    apple;
    banana;
    orange;
    strawberry;
}

Class expression:

const Fruit = class extends Enum() {
    apple;
    orange;
    strawberry;
    banana = "berry";
}

Comparisons:

Fruit.apple == Fruit.orange; // false

Type check:

Fruit.banana instanceof Fruit; // true

Access by key name:

const key = "strawberry";
Fruit[key]; // Fruit.strawberry

Access by value:

Fruit.byValue("orange"); // Fruit.orange
Fruit.byValue("berry"); // Fruit.banana

String representation:

Fruit.banana.toString(); // [enum Fruit(banana)]

JSON representation:

JSON.stringify({fruit: Fruit.banana}); // {"fruit": "berry"}

Notes

Enum members are lazy loaded to the static context of the class on first access.

class Lazy extends Enum() {
    one;
    two;
    three;
}

// Before loading
Object.keys(Lazy); // []

// Trying to access any property will trigger the mixin
Lazy._;

// After loading
Object.keys(Lazy); // ["one", "two", "three"]

To explicitly load the static context you may use the static method initialize.

class Forced extends Enum() {
    one;
    two;
    three;
}
Forced.initialize();

Object.keys(Forced); // ["one", "two", "three"]

Thanks

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