python_backend/app/static/app.js

async function postJson(url, body) {
  const response = await fetch(url, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(body)
  });
  return response.json();
}

function bind(formId, resultId, endpoint, extra = {}) {
  const form = document.getElementById(formId);
  const result = document.getElementById(resultId);
  form.addEventListener("submit", async (event) => {
    event.preventDefault();
    result.textContent = "Procesando...";
    const payload = Object.fromEntries(new FormData(form).entries());
    const data = await postJson(endpoint, { ...payload, ...extra });
    result.textContent = JSON.stringify(data, null, 2);
  });
}

bind("product-form", "product-result", "/api/products", { fuente: "web" });
bind("consume-form", "consume-result", "/api/consume", { fuente: "web-consumo" });