app.js

const express = require("express");
const app = express();

const authorRouter = require("./routes/authorRouter")
const bookRouter = require("./routes/bookRouter")
const indexRouter = require("./routes/indexRouter")

// i guess these are the middleware funcs?
app.use("/authors", authorRouter)
app.use("/books", bookRouter)
app.use("/", indexRouter)

// Every thrown error in the application or the previous middleware function calling `next` with an error as an argument will eventually go to this middleware function
// you need to include 4 params even though they are not used!
app.use((err, req, res, next) => {
  console.error(err);
  res.status(500).send(err);
});


const PORT = 3000;

app.listen(PORT, (error) => {
  if (error) {
    throw error
  }

  console.log(`server listening on port: ${PORT}`)
})