Validators

Sometimes you need more than per-field validation in an action and Validators associated with an action enables that.

export interface Validator<
  TEnt extends Ent<TViewer>,
  TBuilder extends Builder<TEnt, TViewer, TExistingEnt>,
  TViewer extends Viewer = Viewer,
  TInput extends Data = Data,
  TExistingEnt extends TMaybleNullableEnt<TEnt> = MaybeNull<TEnt>,
> {
  validate(builder: TBuilder, input: TInput): Promise<void> | void;
}

Each Validator takes the Builder and the Input.

For example, to validate that the start time is before the end time in the example schema

src/ent/event/actions/event_validators.ts

export class EventTimeValidator
  implements Validator<Event, EventBuilder, Viewer, EventInput> {
  validate(builder: EventBuilder): void {
    const startTime = builder.getNewStartTimeValue();
    const endTime = builder.getNewEndTimeValue();

    if (!startTime) {
      throw new Error("startTime required");
    }

    if (!endTime) {
      // nothing to do here
      return;
    }

    if (startTime.getTime() > endTime.getTime()) {
      throw new Error("start time cannot be after end time");
    }
  }
}

and then update the actions as follows:

/src/ent/event/actions/create_event_action.ts

export default class CreateEventAction extends CreateEventActionBase {
  getValidators() {
    return [
      new EventTimeValidator(),
    ];
  }
}

/src/ent/event/actions/edit_event_action.ts

export default class EditEventAction extends EditEventActionBase {
  getValidators() {
    return [
      new EventTimeValidator(),
    ];
  }
}

so now when creating or editing an event, we'll ensure that the startTime (either new or existing) is before the endTime.

  const user = await getUser();

  // throws error
  await CreateEventAction.create(viewer, {
    name: "fun event",
    creatorID: user.id,
    startTime: new Date('December 25, 2021'),
    endTime: new Date('December 25, 2020'),
    location: "location",
  }).saveX();

  // success
  const event = await CreateEventAction.create(viewer, {
    name: "fun event",
    creatorID: user.id,
    startTime: new Date('December 25, 2021'),
    location: "location",
  }).saveX();

  // throws!
  const event2 = await EditEventAction.create(viewer, event, {
    endTime: new Date('December 25, 2020'),
  }).saveX();