NODEJS, how do I correctly export this method of my Container class to another JS file where I manage express?

Question

[I'm trying to pass my getAll() method of my Container class found in app.js to my appServer.js file to pass it to the res.send() of my app = express() variable and pass that res.send() to the route "/products"

when I try to run the server it throws me an error telling me that Container.getAll() is not a function

I have tried to export using exports.getAll() but it still throws me an error]

[App.js]

const fs = require("fs");

class Contenedor {
  constructor(txtNameFile) {
    this.txtNameFile = txtNameFile;
    this.products = [];
  }

  async fileInJSON() {
    let fileTxt = await fs.promises.readFile(this.txtNameFile, "utf-8");
    let type = JSON.parse(fileTxt);
    return type;
  }

  async fileSaving(item) {
    let type = JSON.stringify(item);
    await fs.promises.writeFile(this.txtNameFile, type);
  }

  async save(obj) {
    try {
      let fileTxt = await fs.promises.readFile(this.txtNameFile, "utf-8");
      if (fileTxt === "") {
        obj.id = 1;
        this.products.push(obj);
      } else {
        const type = JSON.parse(fileTxt);
        obj.id = type[type.length - 1].id + 1;
        type.push(obj);
        this.products = type;
        this.fileSaving(type);
      }
      console.log(
        "El producto se ha guardado en el archivo satisfactoriamente"
      );
      return obj.id;
    } catch (error) {
      console.error("No se ha podido guardar");
    }
  }

  async getById(id) {
    let type = await this.fileInJSON();
    let product = type.find((product) => product.id == id);
    return console.log(product);
  }

  async getAll() {
    let type = await this.fileInJSON();
    return console.log(type);
  }

  async deleteAll() {
    let item = [];
    this.products = item;
    this.fileSaving(item);
  }

  async deleteById(number) {
    let type = await this.fileInJSON();
    let item = type.find((item) => item.id === number);
    let index = type.indexOf(item);
    type.splice(index, 1);
    this.fileSaving(type);
  }
}

module.exports = Contenedor;

[appServer.js]

const express = require("express");
const app = express();
const PORT = 3000;
const Contenedor = require("./app.js");
 

app.get("/", (req, res) => {
  res.send("Ingresa a la ruta /productos para ver los productos :D");
});

app.get("/productos", (req, res) => {
  res.send(Contenedor.getAll());
});

const servidor = app
  .listen(PORT, () => {
    console.log(`Servidor corriendo en el puerto ${PORT}`);
  })
  .on("error", (error) => console.error("FALLASTE" + error));

Answer 1

Maybe you should instantiate a Container object by using new operator.

const express = require("express");
const app = express();
const PORT = 3000;
const Contenedor = require("./app.js");
const myContainer = new Contenedor("example.txt");
 

app.get("/", (req, res) => {
  res.send("Ingresa a la ruta /productos para ver los productos :D");
});

app.get("/productos", (req, res) => {
  res.send(myContainer.getAll());
});

const servidor = app
  .listen(PORT, () => {
    console.log(`Servidor corriendo en el puerto ${PORT}`);
  })
  .on("error", (error) => console.error("FALLASTE" + error));

Answer 2

you should access to that class first.

app.get("/productos", (req, res) => {
    const test_class = new Contenedor()
    res.send(test_class.getAll());
});