Ionic/Angular change Data in Node Server – Twitter API

I have create a Node application that uses the Twit(twitter api) to allow my ionic/Angular Application to post a tweet on twitter, however this problem that I have is that i get a 404 error message when I set the REST method to Post, it seems to work with a GET method.

However I do not know how I can dynamically change the Data in my node application from my Ionic Application.

I want to change the User’s information and the Message that is being sent, but I do not know where to start. if anyone can guide me that will be appriecated.

this is my Node server.js file

const express = require('express');
const Twitter = require('twit');

const app = express();
const client = new Twitter({
  consumer_key:         '...',
  consumer_secret:      '...',
  access_token:         '...',
  access_token_secret:  '...',
});


app.use(require('cors')());
app.use(require('body-parser').json());

app.post('/post_tweet', (req, res) => {

  tweet = {status:"Random"};

    client
      .post(`statuses/update`, tweet)
      .then(timeline => {
        console.log(timeline);

        res.send(timeline);
      })

     .catch(error => {
      res.send(error);
    });


});

app.listen(3000, () => console.log('Server running'));

this is my twitter service in my Ionic application

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { map } from 'rxjs/operators';
@Injectable({
  providedIn: 'root'
})
export class TwitterserviceService {
  api_url = 'http://localhost:3000';

  constructor(private http: HttpClient) { } 

  tweet(tweetdata: string) {
    return this.http.get<any>(`${this.api_url}/post_tweet`)
        .pipe(map(tweet => {

            alert("tweet posted")

            return tweet;
        }));
}
}

and this is the method that I use to send a Post, however the message “this works” doesent post instead the default message in the Node application is sent “random”

sendTweet() {    
  this.api.tweet('this works')
            .pipe(first())
            .subscribe(
                data => {
                    console.log('yes')
                },
                error => {
                  'failed'
                });
}