POST data with user details in mongo db using node.js - node.js

Question

I am developing a web application using the MEAN stack with Angular 6. I have a form to submit data into MongoDB. Following is the save function and it works.
It saves the extruded value in the DB.
saveExtrudedHeightValue(extrudedHeight: NgForm) {
if (extrudedHeight.value != "" && extrudedHeight.value != null) {
this.extrudedHeightService.saveExtrudedHeight(extrudedHeight.value).subscribe(res => {
console.log(res);
}, (err) => {
console.log(err);
});
}
}
Here is the model
// Schema for extruded height panel
var extrudedHeightSchema = new mongoose.Schema({
userName: {
type: String
},
extrudedHeight: {
type: Number
},
});
module.exports = mongoose.model('extrudedHeightValue', extrudedHeightSchema);
Here is my post route
//post extrudedHeight values
router.post("/save", function(req, res) {
var mod = new extrudedHeight(req.body);
extrudedHeight.findOneAndUpdate({
userName: req.body.email,
extrudedHeight: req.body.extrudedHeight,
},
req.body, {
upsert: true,
new: true
},
function(err, data) {
if (err) {
console.log(err);
res.send(err);
} else {
res.send(mod);
}
}
);
});
Here is the service.
// service for save extruded height
saveExtrudedHeight(extrudedHeight): Observable < any > {
return this.http.post('/extrudedHeight/save', extrudedHeight, httpOptions)
.pipe(
catchError(this.handleError)
);
}
Now I want to save data in DB with the current user's userName. I can retrieve the current user's userName by this.
this.payload.user['email']
My problem is that I do not have an idea how to pass this userName to post route to save in db.
Here is where I get token.
this.authService.onTokenChange().subscribe(
(token: NbAuthJWTToken) => {
if (token.isValid()) {
this.user = token.getPayload().user;
this.payload = token.getPayload();
console.log(this.payload.user['email']);
}
}
)

Answer 1

You can first call this.authService.onTokenChange inside the saveExtrudedHeight method, and then use the flatMap operator to unwrap the internal Observable that would be returned by the http.post.
That would translate to code like this:
import { flatMap } from 'rxjs/operators';
import { throwError } from 'rxjs';
...
saveExtrudedHeight(extrudedHeight): Observable<any> {
const requestPayload = {
extrudedHeight
};
return this.authService.onTokenChange()
.pipe(flatMap(
(token: NbAuthJWTToken) => {
if (token.isValid()) {
this.user = token.getPayload().user;
this.payload = token.getPayload();
const email = this.payload.user['email'];
requestPayload.email = email;
// Make the changes here to send the email as the Request Payload.
return this.http.post('/extrudedHeight/save', requestPayload, httpOptions)
.pipe(
catchError(this.handleError)
);
} else {
throwError('Something went wrong!');
}
}
));
}
PS: I'm not really sure if this would work though as I haven't tested it out and I can't without a minimal working StackBlitz.