Explicitly Set Types To Models toJSON Transform Function

Fixes the following error, when running `npm run dev` in the backend:

```
/home/tal/Code/NextStep/nextstep-backend/node_modules/ts-node/src/index.ts:859
    return new TSError(diagnosticText, diagnosticCodes, diagnostics);
           ^
TSError: ⨯ Unable to compile TypeScript:
src/models/user_model.ts:34:13 - error TS2322: Type 'unknown' is not assignable to type 'string'.

34             id: ret._id,
               ~~

  src/types/user_types.ts:13:5
    13     id: string;
           ~~
    The expected type comes from property 'id' which is declared here on type 'UserData'
src/models/user_model.ts:35:13 - error TS2322: Type 'unknown' is not assignable to type 'string'.

35             username: ret.username,
               ~~~~~~~~

  src/types/user_types.ts:14:5
    14     username: string;
           ~~~~~~~~
    The expected type comes from property 'username' which is declared here on type 'UserData'
src/models/user_model.ts:36:13 - error TS2322: Type 'unknown' is not assignable to type 'string'.

36             email: ret.email,
               ~~~~~

  src/types/user_types.ts:15:5
    15     email: string;
           ~~~~~
    The expected type comes from property 'email' which is declared here on type 'UserData'
src/models/user_model.ts:37:13 - error TS2322: Type 'unknown' is not assignable to type 'string'.

37             password: ret.password,
               ~~~~~~~~

  src/types/user_types.ts:16:5
    16     password: string;
           ~~~~~~~~
    The expected type comes from property 'password' which is declared here on type 'UserData'
src/models/user_model.ts:38:13 - error TS2322: Type 'unknown' is not assignable to type 'string | undefined'.

38             imageFilename: ret?.imageFilename,
               ~~~~~~~~~~~~~

  src/types/user_types.ts:17:5
    17     imageFilename?: string;
           ~~~~~~~~~~~~~
    The expected type comes from property 'imageFilename' which is declared here on type 'UserData'
src/models/user_model.ts:39:13 - error TS2322: Type 'unknown' is not assignable to type 'string | undefined'.

39             createdAt: ret.createdAt,
               ~~~~~~~~~

  src/types/user_types.ts:18:5
    18     createdAt?: string,
           ~~~~~~~~~
    The expected type comes from property 'createdAt' which is declared here on type 'UserData'
src/models/user_model.ts:40:13 - error TS2322: Type 'unknown' is not assignable to type 'string | undefined'.

40             updatedAt: ret.updatedAt
               ~~~~~~~~~

  src/types/user_types.ts:19:5
    19     updatedAt?: string,
           ~~~~~~~~~
    The expected type comes from property 'updatedAt' which is declared here on type 'UserData'

    at createTSError (/home/tal/Code/NextStep/nextstep-backend/node_modules/ts-node/src/index.ts:859:12)
    at reportTSError (/home/tal/Code/NextStep/nextstep-backend/node_modules/ts-node/src/index.ts:863:19)
    at getOutput (/home/tal/Code/NextStep/nextstep-backend/node_modules/ts-node/src/index.ts:1077:36)
    at Object.compile (/home/tal/Code/NextStep/nextstep-backend/node_modules/ts-node/src/index.ts:1433:41)
    at Module.m._compile (/home/tal/Code/NextStep/nextstep-backend/node_modules/ts-node/src/index.ts:1617:30)
    at node:internal/modules/cjs/loader:1895:10
    at Object.require.extensions.<computed> [as .ts] (/home/tal/Code/NextStep/nextstep-backend/node_modules/ts-node/src/index.ts:1621:12)
    at Module.load (node:internal/modules/cjs/loader:1465:32)
    at Function._load (node:internal/modules/cjs/loader:1282:12)
    at TracingChannel.traceSync (node:diagnostics_channel:322:14) {
  diagnosticCodes: [
    2322, 2322,
    2322, 2322,
    2322, 2322,
    2322
  ]
}
[nodemon] app crashed - waiting for file changes before starting...
```

**Problem**
In `user_model.ts`, the `transform` function is typed
to return `UserData`, which expects all fields to be
of type `string` (or `string | undefined` for some).
However, the `ret` object passed to the transform
function is not strongly typed—it is inferred as
`any` or `unknown` by TypeScript, especially when
using strict settings.

This fixes all the models` `transform` function.

Signed-off-by: Tal Jacob <taljacob2@gmail.com>

Author: taljacob2

nextstep-backend/src/models/comments_model.ts

@@ -30,12 +30,12 @@ const commentSchema: Schema = new mongoose.Schema({
 commentSchema.set('toJSON', {
     transform: (doc: Document, ret: Record<string, any>) => {
         return {
-            id: ret._id,
-            postId: ret.postId,
-            content: ret.content,
-            owner: ret.owner,
-            createdAt: ret.createdAt,
-            updatedAt: ret.updatedAt,
+            id: ret._id.toString(),
+            postId: ret.postId.toString(),
+            content: ret.content as string,
+            owner: ret.owner.toString(),
+            createdAt: ret.createdAt ? ret.createdAt.toISOString() : undefined,
+            updatedAt: ret.updatedAt ? ret.updatedAt.toISOString() : undefined,
         };
     }
 });

nextstep-backend/src/models/company_model.ts

@@ -46,10 +46,10 @@ const companySchema: Schema = new mongoose.Schema({
 companySchema.set('toJSON', {
     transform: (doc: Document, ret: Record<string, any>) => {
         return {
-            id: ret._id,
-            company: ret.company,
-            company_he: ret.company_he,
-            tags: ret.tags,
+            id: ret._id.toString(),
+            company: ret.company as string,
+            company_he: ret.company_he as string,
+            tags: ret.tags as string[],
             quizzes: ret.quizzes,
         }
     }

nextstep-backend/src/models/posts_model.ts

@@ -25,13 +25,12 @@ const postSchema: Schema = new mongoose.Schema({
 postSchema.set('toJSON', {
     transform: (doc: Document, ret: Record<string, any>): PostData => {
         return {
-            id: ret._id,
+            id: ret._id.toString(),
             title: ret.title,
             content: ret.content,
             owner: ret.owner._id.toString(),
-            createdAt: ret.createdAt,
-            updatedAt: ret.updatedAt
-
+            createdAt: ret.createdAt ? ret.createdAt.toISOString() : undefined,
+            updatedAt: ret.updatedAt ? ret.updatedAt.toISOString() : undefined
         };
     }
 });

nextstep-backend/src/models/user_model.ts

@@ -31,13 +31,13 @@ const userSchema: Schema = new Schema({
 userSchema.set('toJSON', {
     transform: (doc, ret): UserData => {
         return {
-            id: ret._id,
-            username: ret.username,
-            email: ret.email,
-            password: ret.password,
-            imageFilename: ret?.imageFilename,
-            createdAt: ret.createdAt,
-            updatedAt: ret.updatedAt
+            id: ret._id.toString(),
+            username: ret.username as string,
+            email: ret.email as string,
+            password: ret.password as string,
+            imageFilename: ret?.imageFilename as string | undefined,
+            createdAt: ret.createdAt ? ret.createdAt.toISOString() : undefined,
+            updatedAt: ret.updatedAt ? ret.updatedAt.toISOString() : undefined
         };
     }
 });