Author: John Au-Yeung

To use populate and aggregate in same statement with Node Mongoose, we call the populate method.

For instance, we write

Patients.populate(result, { path: "patient" }, callback);

to call the populate method with result and an object with the fields to get to populate the result.

callback is a function with the results.

To fix Error: Cannot GET / witn Node Express, we add render a template or expose a static folder.

For instance, we write

app.use(express.static(__dirname + "/public"));

app.get("/", (req, res) => {
  res.render("index.ejs");
});

to call app.use with the middleware returned by express.static to expose the /public folder as a static files folder.

We also add a get / route to render the index.ejs template.

To fix ENOENT, no such file or directory with Node npm, we clear the npm cache.

To do this, we

1. Run npm install
2. Run npm cache clean to clear the npm cache
3. Run npm install -g npm, then npm install

To get the redirected URL from the Node request module, we use the request property.

For instance, we write

const request = require("request");
const r = request.get("http://example.com", (err, res, body) => {
  console.log(res.request.uri.href);
});

to make a get request with request.get.

We get the redirect URL from the res.request.url.href property.

To solve "ReferenceError: expect is not defined" error message with Node, we install chai.

To install it, we run

npm install chai

Then we write

const expect = chai.expect;

to get the chai.expect property.