how to send data from angular to node.js - node.js

Question

i need to pass some data from angular to node.js server. this is my angular postlist component:
import { Component, OnInit } from '#angular/core';
import { HttpClient } from "#angular/common/http";
#Component({
selector: 'app-postlist',
templateUrl: './postlist.component.html',
styleUrls: ['./postlist.component.css']
})
export class PostlistComponent implements OnInit {
constructor(private http: HttpClient) { }
public data="test";
ngOnInit(): void {
this.http
.post("http://localhost:3000/api/book",this.data);
}
}
my node.js server:
const express=require('express');
var app = express();
app.post('/api/book', function(req, res, next){
var data = req.body.params;
console.log(data);
});
app.listen(3000);
i'm trying to console.log the data but nothing happens.

Answer 1

you are missing .subscribe in your call. Change your code to :-
ngOnInit(): void {
this.http
.post("http://localhost:3000/api/book",this.data).subscribe();
}
and in nodejs just print req.body

Answer 2

If you are planning on printing the payload this.data, take req.body instead of req.body.params.
And also check if you have any cors errors in console, that can also be blocking your data from reaching your web server.

Answer 3

in the server, you must change the format of your message to JSON like this
app.get('/api/GetFlux',function(req,resp){
let data = "hello"
resp.send(JSON.stringify(data));
})
at angular level
GetFlux():Observable<any[]>{
return this.http.get<any>(this.APIUrlNode+'/GetFlux');
}
this.service.GetFlux().subscribe(res =>{
this.fluxList = {
data:res
}
console.log("Data from node "+this.fluxList.data)
//,
}, err => {
console.log(" err = "+err)
})