Typeorm-state-machine NPM

Typeorm State Machine

Declarative state machine definition for typeorm entity classes Based on javascript-state-machine implementation

Why?

Usage

Imagine you have some payment model. This payment has statuses:

new
registered
held
charged
error
refunded

enum Status {
    NEW = 'new',
    REGISTERED = 'registered',
    HELD = 'held',
    CHARGED = 'charged',
    ERROR = 'error',
    REFUNDED = 'refunded',
}

@StateMachine({
    transitions: [
        { name: 'register', from: Status.NEW, to: Status.REGISTERED },
        { name: 'hold', from: Status.REGISTERED, to: Status.HELD },
        { name: 'charge', from: Status.HELD, to: Status.CHARGED },
        { name: 'fail', from: [Status.NEW, Status.HELD, STATUS.REGISTERED], to: Status.ERROR },
        { name: 'refund', from: Status.CHARGED, to: Status.REFUNDED },
    ]
})
@Entity()
class Payment {
    @Column()
    guid: string;

    @Column()
    externalId: string;

    @Column()
    amount: number;

    @Column()
    status: Status;
}

Also you need interface with these methods and same name as entity

interface Payment {
    register(): void;
    hold(): void;
    charge(): void;
    fail(): void;
    refund(): void;
}

After the entity will be loaded - state machine initialized with proper status. And you can use methods from interface which was implemented while entity loading

payment.register();
payment.hold();
payment.charge();
payment.refund();

payment.register() // will fail, becauze it is incorrect state transition

Options

saveAfterTransition - all transitions become promisified and you can use it like await payment.hold(). Entity is also will be saved in database (Default false)
autoImplementAll - all methods provided in state machine definition are auto implemented while loading. (Default true)