Feathers: Hook typing and find method parsing issue

[soullivaneuh]

I use the Hook type when declaring my hook:

type PushToken = {
  token: string;
  applicationSlug: string;
  createdAt?: Date;
}

const handleCreate: Hook<PushToken> = ({ data, service, result }) => {
  if (!data) {
    return;
  }
  const { token, applicationSlug } = data;

  return service
    .find({ query: { token }, paginate: false })
    .then((tokens) => tokens.length)
  ;
}

Works fine, except for the last then callback.

The tokens.length throw the following typescript error:

Property 'length' does not exist on type 'PushToken | PushToken[] | Paginated<PushToken>'.
  Property 'length' does not exist on type 'PushToken'.ts(2339)

This is caused by the following signature:

find (params?: Params): Promise<T | T[] | Paginated<T>>;

I may have only one instance but also an array or a Paginated instance.

So I tried to force the typing like this:

.then((tokens: PushToken[]) => tokens.length)

But then give me now an error on the function typing itself:

Argument of type '(tokens: PushToken[]) => number' is not assignable to parameter of type '(value: PushToken | PushToken[] | Paginated<PushToken>) => number | PromiseLike<number>'.
  Types of parameters 'tokens' and 'value' are incompatible.
    Type 'PushToken | PushToken[] | Paginated<PushToken>' is not assignable to type 'PushToken[]'.
      Type 'PushToken' is missing the following properties from type 'PushToken[]': length, pop, push, concat, and 26 more.ts(2345)

The only way I have to get rid of this error is to set the any type to my tokens params, but I loose all the interest of typescript then.

Not sure if it's a bug, but I can't find any reliable example for that on the documentation.

[soullivaneuh]

Got the same issue with patch:

const handleCreate: Hook<PushTokensData, PushTokens> = (context) => {
  const { service, params, data } = context;
  if (!params.user) {
    throw new Error('This hook must be under authentication.');
  }
  if (!data) {
    return;
  }
  const { token } = data;
  data.userId = params?.user?._id;
  data.pingedAt = new Date();

  return service
    .find({ query: { token }, paginate: false })
    // @see https://github.com/feathersjs/feathers/issues/2147
    .then((resolvedTokens: any) => resolvedTokens.length ? resolvedTokens[0] : undefined)
    .then((resolvedToken: PushTokensData) => {
      if (token) {
        return service.patch(resolvedToken._id, data)
          .then((patchedToken) => {
            context.result = patchedToken;

            return context;
          });
      }
    })
  ;
}

Throwing me this:

src/services/push-tokens/push-tokens.hooks.ts:48:13 - error TS2322: Type 'PushTokensData | PushTokensData[]' is not assignable to type 'PushTokensData | undefined'.
  Type 'PushTokensData[]' is missing the following properties from type 'PushTokensData': _id, token, applicationSlug, userId, pingedAt

48             context.result = patchedToken;
               ~~~~~~~~~~~~~~

Am I missing something? I currently have no solution except putting any everywhere. :-/

[soullivaneuh]

The patch case may be manged with a simple Array.isArray usage.

However:

1. If we patch only one resource, we will always get a object instance, not an array. This is cumbersome for its implementation. We may separate patch onto two methods: patch and patchMultiple with a stricter typing (same for update)
2. The find case is still more complicated because of the Paginated interference. I am not sure about the solution here.

Any though about this?

[soullivaneuh]

I tried some successful things. Here is the story.

First, I created an override of the common service adapter:

// src/adapter.ts
import { NullableId, Paginated, Params } from '@feathersjs/feathers';
import { AdapterService as BaseAdapterService } from '@feathersjs/adapter-commons';

const resultToOne = <T>(value: T | T[]): T => {
  if (Array.isArray(value)) {
    throw new Error('The expected result should not be an array.');
  }

  return value;
}

export class AdapterService<T = any> extends BaseAdapterService<T> {
  createOne(data: Partial<T> | Partial<T>[], params?: Params): Promise<T> {
    return this.create(data, params).then(resultToOne);
  }

  patchOne(id: NullableId, data: Partial<T>, params?: Params): Promise<T> {
    return this.patch(id, data, params).then(resultToOne);
  }

  findPaginated(params?: Params): Promise<Paginated<T>> {
    if (params?.paginate === false) {
      throw new Error('You must not deactivate the pagination on this method.');
    }

    return this.find(params).then((result) => {
      if (Array.isArray(result)) {
        throw new Error('The expected result should be paginated.');
      }

      return result;
    });
  }

  findAll(params?: Params): Promise<T[]> {
    if (typeof params?.paginate !== undefined && params?.paginate !== false) {
      throw new Error('You must not configure the pagination on this method.');
    }

    return this.find({
      ...params,
      paginate: false,
    }).then((result) => {
      if (!Array.isArray(result)) {
        throw new Error('The expected result should not be paginated.');
      }

      return result;
    });
  }
}

Then I use it to declare my application typing:

// src/declarations.d.ts
import { ServiceAddons } from '@feathersjs/feathers';
import { Application as ExpressFeathers } from '@feathersjs/express';
import '@feathersjs/transport-commons';
import { AdapterService } from './src/adapter';

export interface ServiceData {
  _id?: string;
}

export interface UsersData extends ServiceData {
  name: string;
  firstName: string;
  lastName: string;
}

type Service<T> = AdapterService<T> & ServiceAddons<T>;
export interface ServiceTypes {
  'users': Service<UsersData>;
}

And it works perfectly fine allowing me to get the expected result without having the typescripts error I described:

app.service('users').patchOne(
  // ...
).then((myOnlyOneUser) => {
  // ...
});

However, it does not works with the service provided by the hook context:

const myHook: Hook<UsersData> = (context) => {
  const { service } = context;
  // This following method call is not recognized by Typescript.
  service.patchOne();

Any clue about how to solve this would be welcomed.

I may not done it the right way. However, this new methods I created simplify a lot the implementation code complexity, increasing the productivity. Also, it makes sense to me to have this hack placed at this place.

If you agree, we may discuss about a merge request proposal here.

Thanks for reading.

[soullivaneuh]

I just found how to get the service typing working properly on a hook context, here is an another sample:

First, I have to export my custom service type in addition to the global definition:

@@ -83,6 +83,8 @@ export interface UsersData extends ServiceData {
 }

 type Service<T> = AdapterService<T> & ServiceAddons<T>;
+
+export type PushTokensService = Service<PushTokensData>;
 export interface ServiceTypes {
   'auth-sms': Service<AuthSmsData>;
   'billing-departments': Service<BillingDepartmentsData>;
@@ -90,7 +92,7 @@ export interface ServiceTypes {
   'credit-cards': Service<any>;
   'notifications': Service<NotificationsData>;
   'postal-codes': Service<any>;
-  'push-tokens': Service<PushTokensData>;
+  'push-tokens': PushTokensService;
   'rides': Service<any>;
   'sms': Service<any>;
   'transactions': Service<any>;

Then import and use the related service:

const handleCreate: Hook<PushTokensData, PushTokensService> = (context) => {
  // Your awesome code here.
}

Update: If you don't want to declare tons of service type, you may directly use the right service that way:

const handleCreate: Hook<PushTokensData, ServiceTypes['push-tokens']> = (context) => {

Update Bis: This is not working properly:

src/services/push-tokens/push-tokens.service.ts:17:17 - error TS2345: Argument of type '{ before: { all: (IffHook | ((context: HookContext<any, Service<any>>) => Promise<HookContext<any, Service<any>>>))[]; ... 5 more ...; remove: never[]; }; after: { ...; }; error: { ...; }; }' is not assignable to parameter of type 'Partial<HooksObject<any>>'.
  Types of property 'before' are incompatible.
    Type '{ all: (IffHook | ((context: HookContext<any, Service<any>>) => Promise<HookContext<any, Service<any>>>))[]; find: IffHook[]; ... 4 more ...; remove: never[]; }' is not assignable to type 'Hook<any, Service<any>> | Hook<any, Service<any>>[] | Partial<HookMap<any>> | undefined'.
      Type '{ all: (IffHook | ((context: HookContext<any, Service<any>>) => Promise<HookContext<any, Service<any>>>))[]; find: IffHook[]; ... 4 more ...; remove: never[]; }' is not assignable to type 'Partial<HookMap<any>>'.
        Types of property 'create' are incompatible.
          Type '(Hook<any, Service<any>> | Hook<PushTokensData, Service<PushTokensData>>)[]' is not assignable to type 'Hook<any, Service<any>> | Hook<any, Service<any>>[] | undefined'.
            Type '(Hook<any, Service<any>> | Hook<PushTokensData, Service<PushTokensData>>)[]' is not assignable to type 'Hook<any, Service<any>>[]'.
              Type 'Hook<any, Service<any>> | Hook<PushTokensData, Service<PushTokensData>>' is not assignable to type 'Hook<any, Service<any>>'.
                Type 'Hook<PushTokensData, Service<PushTokensData>>' is not assignable to type 'Hook<any, Service<any>>'.
                  Types of parameters 'context' and 'context' are incompatible.
                    Type 'HookContext<any, Service<any>>' is not assignable to type 'HookContext<PushTokensData, Service<PushTokensData>>'.
                      Type 'Service<any>' is not assignable to type 'Service<PushTokensData>'.
                        Type 'ServiceOverloads<any> & ServiceAddons<any> & ServiceMethods<any>' is missing the following properties from type 'AdapterService<PushTokensData>': createOne, patchOne, findPaginated, findAll, and 4 more.

17   service.hooks(hooks);
                   ~~~~~

[soullivaneuh]

It looks like I am limited with hook because it expects this service type: https://github.com/feathersjs/feathers/blob/58f1ed3659ff4ef6815883ea6366bdca8c0095f6/packages/feathers/src/declarations.ts#L208

However, I don't know how to properly integrate my service override on them.

[soullivaneuh]

Finally my setup works only for typing, according to the test:

 FAIL  test/services/transactions.test.ts
  ● transaction creation › creates as an admin

    TypeError: app_1.default.service(...).patchOne is not a function

      73 |   }
      74 |   if (!toUser.mangoPayId) {
    > 75 |     toUser = await app.service('users').patchOne(toUser._id, {
         |                                         ^
      76 |       mangoPaySetup: true,
      77 |     });
      78 |   }

      at Object.handleCreate (src/services/transactions/transactions.hooks.ts:75:41)

I am quite lost here. How can I bring my function to the app? My app.ts file looks limited for this:

const app: Application = express(feathers());

[daffl]

This will be addressed in the upcoming version with a bunch of other (probably breaking) TypeScript changes. Unfortunately there currently is no other option than to force cast it at the moment.

[soullivaneuh]

Thanks for the feedback @daffl!

You says it is planned. Do you have an issue to reference? :thinking:

[soullivaneuh]

@daffl May this issue being added on the v5 milestone then? https://github.com/feathersjs/feathers/milestone/11

By the way, do you have an already existing issue of this milestone to refer that is related to the exposed problematic?

Thanks!

[daffl]

Yes, this will be included in the v5 refactoring with a pull request incoming shortly.