Estoy atascado en algo muy trivial tratando de construir mi interfaz. Mi main.js se ve así:

 const textfield = document.getElementById('inpTextField') const btnSendPost = document.getElementById('btnSendPost') btnSendPost.addEventListener('click', () => { sendData() }) function sendData() { let txtValue = textfield.value console.log(txtValue) let sendingJSON = { "body" : `${txtValue}` } fetch("http://localhost:3000/post", { method: "post", body: JSON.stringify(sendingJSON), headers: { "Content-Type": "application.json"} }) .then(res => res.json()) .then(json => console.log(json)) .catch(err => console.log(err)) }

pero mi backend (express 4.18) no registra la solicitud POST, y la consola devuelve enigmático:

 TypeError: Failed to fetch at <anonymous>:1:876 at sendData (main.js:17:5) at HTMLButtonElement.<anonymous> (main.js:7:5)

index.js (programa de fondo)

 const express = require('express') const app = express() const port = 3000 const bp = require('body-parser') let randomJson = { "apple" : "cider viegar" } app.use(bp.json()) app.use(bp.urlencoded(({ extended: true}))) app.get('/',(req,res) => { res.json(randomJson) }) app.post('/post', (req, res) => { var body = req.body console.log(body) res.send("ok") }) app.listen(port, () => { console.log(`Server running on ${port}`) })

algunas ideas ?