Short Links: Redirect

The app stores short links, but a short link is only useful if opening it takes you to the long URL. A short link is the app's address, a slash, then the code: /1, /zz.

Any text in the path: in a route like "/:code", the part that starts with a colon is a path parameter. It takes any text between the slashes, and Express puts that text, as a string, in req.params under the name after the colon. That suits codes made of digits and letters.

Is the key there? Object.hasOwn(prices, "tea") is true when the object prices has a key "tea" that you stored. It doesn't count the names every object has built in, like toString.

Redirects: res.redirect(302, url) sends an answer with the status 302 Found and a Location header set to the URL. The answer has no page of its own: a browser that gets it opens that URL right away. For example, on another route:

app.get("/docs", (req, res) => {
  res.redirect(302, "https://expressjs.com/");
});

After two POST /links made the codes 1 and 2, your app must give these answers, in this order:

GET /1   →  302  Location: https://www.python.org/downloads/
GET /2   →  302  Location: https://en.wikipedia.org/wiki/URL_shortening
GET /3   →  404  {"error": "Link not found"}
GET /zz  →  404  {"error": "Link not found"}
POST /links  {"url": "https://flask.palletsprojects.com/en/stable/quickstart/"}
         →  201  {"code": "3", "url": "https://flask.palletsprojects.com/en/stable/quickstart/"}
GET /3   →  302  Location: https://flask.palletsprojects.com/en/stable/quickstart/

Your task: at the end of the file, add GET /:code. When links doesn't have the code, answer 404 with {"error": "Link not found"}; otherwise redirect to the stored URL with the status 302.

Assignment
Follow the Coding Tutorial to add the GET /:code route that sends a short link on to its long URL.

Hint
The name after req.params. is the same as the name after the colon in the path. Check for a missing code first and return the 404; only then read links[code].