Add Contextual<Service, Context> type

As seen in TeamService2.ts, the Contextual type will add Context as the
last argument to any method of the interface, as long as the method has
0-4 arguments.

Interfaces with more than 4 arguments cannot use this type, but they
could be converted to interfaces which use 1 argument
(object/dictionary) only.

Some long-term thinking: Maybe only methods with a single argument
should be supported, similar to the way gRPC does it.

packages/common/src/team.ts

@@ -24,24 +24,24 @@ export interface IContext {
   userId: number
 }
 
-type Contextual<T> = (context: IContext) => Promise<T>
-
 export interface ITeamService {
-  create(params: ITeamCreateParams): Contextual<ITeam>
+  jerko(params: string): number
 
-  remove(params: ITeamRemoveParams): Contextual<{id: number}>
+  create(params: ITeamCreateParams): Promise<ITeam>
 
-  update(params: ITeamUpdateParams): Contextual<ITeam>
+  remove(params: ITeamRemoveParams): Promise<{id: number}>
 
-  addUser(params: ITeamAddUserParams): Contextual<IUserInTeam>
+  update(params: ITeamUpdateParams): Promise<ITeam>
 
-  removeUser(params: ITeamAddUserParams): Contextual<ITeamAddUserParams>
+  addUser(params: ITeamAddUserParams): Promise<IUserInTeam>
+
+  removeUser(params: ITeamAddUserParams): Promise<ITeamAddUserParams>
 
   findOne(id: number): Promise<ITeam | undefined>
 
-  find(userId: number): Contextual<ITeam[]>
+  find(): Promise<ITeam[]>
 
-  findUsers(teamId: number): Contextual<IUserInTeam[]>
+  findUsers(teamId: number): Promise<IUserInTeam[]>
 
   // TODO add other methods
 }

packages/jsonrpc/src/types.ts

@@ -9,6 +9,25 @@ type RetProm<T> = T extends Promise<any> ? T : Promise<T>
 type PromisifyReturnType<T> = (...a: ArgumentTypes<T>) =>
   RetProm<UnwrapHOC<RetType<T>>>
 
+/**
+ * Helps implement a service from a service definiton that has a context as a
+ * last argument.
+ */
+export type Contextual<T, Cx> = {
+  [K in keyof T]:
+    T[K] extends () => infer R
+      ? (cx: Cx) => R :
+    T[K] extends (a: infer A) => infer R
+      ? (a: A, cx: Cx) => R :
+    T[K] extends (a: infer A, b: infer B) => infer R
+      ? (a: A, b: B, cx: Cx) => R :
+    T[K] extends (a: infer A, b: infer B, c: infer C) => infer R
+      ? (a: A, b: B, c: C, cx: Cx) => R :
+    T[K] extends (a: infer A, b: infer B, c: infer C, d: infer D) => infer R
+      ? (a: A, b: B, c: C, d: D, cx: Cx) => R :
+    never
+}
+
 export type FunctionPropertyNames<T> = {
   [K in keyof T]: K extends string
     ? T[K] extends (...args: any[]) => any

packages/server/src/services/TeamService2.ts

@@ -8,16 +8,21 @@ import {
   team as t,
   IUserInTeam,
 } from '@rondo/common'
+import {Contextual} from '@rondo/jsonrpc'
 
 type IContext = t.IContext
 
-export class TeamService2 implements t.ITeamService {
+export class TeamService2 implements Contextual<t.ITeamService, IContext> {
   constructor(
     protected readonly db: DB,
     protected readonly permissions: IUserPermissions,
   ) {}
 
-  create = (params: t.ITeamCreateParams) => async (context: IContext) => {
+  jerko(params: string, context?: IContext): number {
+    return parseInt(params, 10)
+  }
+
+  async create(params: t.ITeamCreateParams, context: IContext) {
     const {userId} = context
     const name = trim(params.name)
 
@@ -36,12 +41,12 @@ export class TeamService2 implements t.ITeamService {
       userId,
       // ADMIN role
       roleId: 1,
-    })(context)
+    }, context)
 
     return team
   }
 
-  remove = ({id}: t.ITeamRemoveParams) => async (context: IContext) => {
+  async remove({id}: t.ITeamRemoveParams, context: IContext) {
     const {userId} = context
 
     await this.permissions.belongsToTeam({
@@ -58,7 +63,7 @@ export class TeamService2 implements t.ITeamService {
     return {id}
   }
 
-  update = ({id, name}: t.ITeamUpdateParams) => async (context: IContext) => {
+  async update({id, name}: t.ITeamUpdateParams, context: IContext) {
     await this.permissions.belongsToTeam({
       teamId: id,
       userId: context.userId,
@@ -74,7 +79,7 @@ export class TeamService2 implements t.ITeamService {
     return (await this.findOne(id))!
   }
 
-  addUser = (params: t.ITeamAddUserParams) => async (context: IContext) => {
+  async addUser(params: t.ITeamAddUserParams, context: IContext) {
     const {userId, teamId, roleId} = params
     await this.db.getRepository(UserTeam)
     .save({userId, teamId, roleId})
@@ -90,7 +95,7 @@ export class TeamService2 implements t.ITeamService {
     return this.mapUserInTeam(userTeam!)
   }
 
-  removeUser = (params: t.ITeamAddUserParams) => async (context: IContext) => {
+  async removeUser(params: t.ITeamAddUserParams, context: IContext) {
     const {teamId, userId, roleId} = params
 
     await this.permissions.belongsToTeam({
@@ -109,7 +114,8 @@ export class TeamService2 implements t.ITeamService {
     return this.db.getRepository(Team).findOne(id)
   }
 
-  find = () => async ({userId}: IContext) => {
+  async find(context: IContext) {
+    const {userId} = context
     return this.db.getRepository(Team)
     .createQueryBuilder('team')
     .select('team')
@@ -118,7 +124,7 @@ export class TeamService2 implements t.ITeamService {
     .getMany()
   }
 
-  findUsers = (teamId: number) => async (context: IContext) => {
+  async findUsers(teamId: number, context: IContext) {
     await this.permissions.belongsToTeam({
       teamId,
       userId: context.userId,

packages/server/tsconfig.esm.json

@@ -4,8 +4,7 @@
     "outDir": "esm"
   },
   "references": [
-    {
-      "path": "../common/tsconfig.esm.json"
-    }
+    {"path": "../common/tsconfig.esm.json"},
+    {"path": "../jsonrpc/tsconfig.esm.json"}
   ]
-}
+}

packages/server/tsconfig.json

@@ -5,6 +5,7 @@
     "rootDir": "src"
   },
   "references": [
-    {"path": "../common"}
+    {"path": "../common"},
+    {"path": "../jsonrpc"}
   ]
 }