Fetch blocked by cors policy? url shortener

I’m unsure why this is now happening as I have done the previous challenges on the same project and did not run into this issue. The error occurs when I run the tests and reads as follows:

Access to fetch at ‘https://aidan-sabin-portfolio.herokuapp.com/api/shorturl’ from origin ‘https://www.freecodecamp.org’ has been blocked by CORS policy: No ‘Access-Control-Allow-Origin’ header is present on the requested resource. If an opaque response serves your needs, set the request’s mode to ‘no-cors’ to fetch the resource with CORS disabled.

I have no idea how to get around this as nothing I google makes a lot of sense to me.

GitHub Repo: aidan-sabin-portfolio-web-app/server.js at gomix · aidansabin/aidan-sabin-portfolio-web-app · GitHub
Heroku App: https://aidan-sabin-portfolio.herokuapp.com/

server.js file:

// init project
var express = require('express');
var mongodb = require('mongodb');
var mongoose = require('mongoose');
var bodyParser = require('body-parser');
var dns = require('dns');
var app = express();
var port = process.env.PORT || 3000;

// enable CORS (https://en.wikipedia.org/wiki/Cross-origin_resource_sharing)
// so that your API is remotely testable by FCC
var cors = require('cors');
app.use(cors({optionsSuccessStatus: 200}));  // some legacy browsers choke on 204

mongoose.connect(process.env.MONGO_URI, { useNewUrlParser: true, useUnifiedTopology: true });

// http://expressjs.com/en/starter/static-files.html

app.get("/", function (req, res) {
  res.sendFile(__dirname + '/views/index.html');

app.get("/timestamp", function (req, res) {
  res.sendFile(__dirname + '/views/timestamp.html');

app.get("/header-parser", function (req, res) {
  res.sendFile(__dirname + '/views/header-parser.html');

app.get("/url-shortener", function (req, res) {
  res.sendFile(__dirname + '/views/url-shortener.html');

//Timestamp Microservice (no date_string)
app.get("/api", function (req, res) {
    "unix": Date.now(),
    "utc": new Date(Date.now()).toUTCString()

//Request Header Parser Microservice
app.get("/api/whoami", function (req, res) {
    ipaddress: req.connection.remoteAddress,
    language: req.headers['accept-language'],
    software: req.headers['user-agent']

//Url-Shortener Microservice
var Schema = mongoose.Schema;
var UrlData = mongoose.model("UrlData", new Schema({
  original_url: String,
  short_url: String

var shortId;
UrlData.countDocuments({}, function (err, num) {
  if (err) return console.error(err);
  shortId = num + 1;
  return shortId;

app.post("/api/shorturl", function (req, res) {
  let url = req.body.url;
  if (/\/$/.test(url)) {
    url = url.replace(/\/$/, "");
  if (/^(https:\/\/(?!www.)|http:\/\/(?!www.))/.test(url)) {
    url = url.replace(/^(https:\/\/|http:\/\/)/, "www.");
  } else if (/^(https:\/\/(?=www.)|http:\/\/(?=www.))/.test(url)) {
    url = url.replace(/^(https:\/\/www.|http:\/\/www.)/, "www.");
  dns.lookup(url, function (err, address) {
    if (err) {
      return res.json({
        error: "invalid url"
  let newUrl = new UrlData({
    original_url: url,
    short_url: shortId
  UrlData.findOne({ original_url: newUrl.original_url }, (err, data) => {
    if (err) return console.error(err);
    if (data !== null) {
      return res.json({ original_url: data.original_url, short_url: data.short_url });
    } else {
      return res.json({ original_url: newUrl.original_url, short_url: newUrl.short_url });

app.get("/api/shorturl/:short_code", function (req, res) {
  let shortUrl = req.params.short_code;
  UrlData.findOne({ short_url: shortUrl }, function (err, data) {
    if (err) return console.error(err);
    if (data.original_url.match(/http/ig)) {
      return res.status(301).redirect(data.original_url);
    } else {
      return res.status(301).redirect("https://" + data.original_url);

//Timestamp Microservice (with date_string)
app.get("/api/:date_string", function (req, res) {
  let dateString = req.params.date_string;
  let date = new Date(dateString);
  let unix = date.getTime();;
  if (parseInt(dateString).toString().length > 4) {
    date = new Date(parseInt(dateString));
    unix = parseInt(dateString);
  if (date == "Invalid Date") {
    res.json({ "error" : "Invalid Date" });
  } else {
      "unix": unix,
      "utc": date.toUTCString()

// listen for requests
var listener = app.listen(port, function () {
  console.log('Your app is listening on port ' + listener.address().port);

Do you mean when you submit? I’m seeing a 404 when I try to submit your project.

Request URL: https://aidan-sabin-portfolio.herokuapp.com/url-shortener/api/shorturl
Request Method: POST
Status Code: 404 Not Found

The same happens with the other projects. Didn’t really look into it, but maybe it’s related to heroku or the use of subdirectories.

Yeah I mean when I submit it. Also, I meant that the previous versions of the project had no problems passing the test so it is an issue only now that I have added the Url Shortener to it.

Anybody got any workarounds?

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