Author: John Au-Yeung

To get all the values that contains part of a string using Node Mongoose find, we can search with a regex.

For instance, we write

Books.find({ authors: /Alex/i }, (err, docs) => {});

to call find with an object that has authors set to the regex with the pattern we’re looking for.

And we get the results from the docs array.

We use the i flag to search in a case insensitive manner.

To get HTTP headers with Node.js, we use the headers property.

For instance, we write

const http = require("http");
const options = { method: "HEAD", host: "example.com", port: 80, path: "/" };
const req = http.request(options, (res) => {
  console.log(JSON.stringify(res.headers));
});
req.end();

to call http.request with the options to make a get request.

And we get the response headers with res.headers in the callback.

To fix "ERROR: dbpath (/data/db) does not exist." with Node MongoDB, we should make sure the /data/db folder exists.

To do this, we run

sudo mkdir -p /data/db/

to create the /data/db/ folder.

Then we set the current user as the owner of the folder with

sudo chown `id -u` /data/db

To get the latest and oldest record in Node Mongoose.js, we use the sort method.

For instance, we write

Tweet.findOne()
  .sort("-created_at")
  .exec((err, post) => {
    //...
  });

to call sort to sort the results by the created_at field in descending order.

Then we get the latest result from post in the callback.

To find Cannot find module ‘bcrypt’ error with Node, we install a few packages.

To fix this, we run

npm install node-gyp -g
npm install bcrypt -g

npm install bcrypt --save

to install node-gyp and bcrypt globally.

Then we run

npm install bcrypt --save

to install bcrypt locally.