copyapp-backend/index.js

const fs = require("node:fs");
const express = require("express");
const app = express();
const port = 7788;
const data = "./data.json";

app.use(express.json());

// Add Access Control Allow Origin headers AAAAAAAAAAAAAAAAAAAAAA
app.use((req, res, next) => {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.header(
    "Access-Control-Allow-Headers",
    "Origin, X-Requested-With, Content-Type, Accept",
  );
  next();
});

// Returns the contents of 'data.json' when client makes a GET req @ /api/text
app.get("/api/text", (req, res) => {
  fs.readFile("data.json", "utf8", (err, data) => {
    if (err) {
      res.send(err);
      return;
    }
    res.send(data);
  });
});

// Accepts a JSON array of utf-8 character codes, and adds it to the array in data.json
app.post("/api/add", (req, res) => {
  let text = "";
  if (req.body) {
    text = req.body;
    console.log("REQUESTED TEXT: " + text);
  } else {
    // returns when theres no body
    console.log("ERROR (add call): THERES NO BODY");
    res.send("ERROR: NO BODY SPECIFIED");
    return;
  }

  // read the data.json file, store contents in data parameter
  fs.readFile("data.json", "utf8", (err, data) => {
    if (err) {
      res.send(err);
      return;
    }

    // convert the raw json into a JS object
    let storedArray = JSON.parse(data);
    console.log("JSON ARRAY READ FROM data.json: ", storedArray);

    let newArray = [];
    // add each element of the read data and add it to newArray
    for (let i in storedArray) {
      newArray.push(storedArray[i]);
    }

    // add the requested text
    newArray.push(text);
    console.log("JS ARRAY AFTER CHANGES: ", newArray);

    let arrjson = JSON.stringify(newArray);
    console.log("JSON ARRAY TO WRITE: ", arrjson);

    // write the JSON array to data.json
    fs.writeFileSync("data.json", arrjson);

    // send back the input (for no reason)
    res.send(text);
  });
});

app.post("/api/remove", (req, res) => {
  let id = null;
  if (req.body) {
    id = req.body;
    console.log("REQUESTBODY: ", req.body);
  } else {
    // return when theres no body
    console.log("ERROR (remove call): THERES NO BODY");
    res.send("ERROR: NO BODY SPECIFIED");
    return;
  }
  // the body looks like:  { "id": 3 }, so we need to convert it to a number
  id = id["id"];
  console.log("REQUESTED ID: ", id);

  // read the data from json file
  fs.readFile("data.json", "utf8", (err, data) => {
    if (err) {
      res.send(err);
      return;
    }

    // convert raw JSON data into a JS object
    let storedArray = JSON.parse(data);
    console.log("JSON ARRAY READ FROM data.json: ", storedArray);

    // add each element of the read data and add it to newArray
    let newArray = [];
    for (let i in storedArray) {
      newArray.push(storedArray[i]);
    }

    // remove the requested ID
    newArray.splice(id, 1);
    console.log("JS ARRAY AFTER CHANGES: ", newArray);

    let arrjson = JSON.stringify(newArray);
    console.log("JSON ARRAY TO WRITE: ", arrjson);

    fs.writeFileSync("data.json", arrjson);
  });
  // send back id for no reason
  res.send(id);
});

// listen for requests
app.listen(port, () => {
  console.log(`Example app listening on port ${port}`);
});