exercise_1

Exercise 1 - Introduction to Node.js

#1 Create a Node.js script

Create a file app.js with the following code:

console.log('Welcome to Techladies!')

Save it.

Now, in your terminal, type node app.js.

You should see your message printed on the terminal.

Congratulations! You've created your first node.js script! 🎉 🎉

#2 Create a Node.js project

Let's create a node.js project with npm. Type npm init. The utility will walk you through the process of creating a package.json file. When you are prompted to specify an entry point, make sure it is app.js. For everything else, press enter to accept the suggested defaults.

You should now have a package.json file.

Let's go ahead and add a script to our package.json to run node app.js when we type npm start.

In your package.json file, add "start": "node app.js" inside scripts.

Your package.json should now look like this:

{
  "name": "solution",
  "version": "1.0.0",
  "description": "",
  "main": "app.js",
  "scripts": {
    "start": "node app.js",
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC"
}

Save the file.

Now type npm start in your terminal and press enter. You should see your message printed again!

#3 Install a package

We'll now learn how to install a package.

Type npm install upper-case --save.

You should see something similar to this.

npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN solution@1.0.0 No description
npm WARN solution@1.0.0 No repository field.

+ upper-case@2.0.1
added 2 packages from 2 contributors and audited 2 packages in 1.059s
found 0 vulnerabilities

Verify that your package.json has a new entry upper-case under dependencies.

Now, modify your app.js file to look like the one below:

var uc = require('upper-case');

console.log(uc.upperCase("Welcome to Techladies"))

Run npm start again. Do you see something different? 😄

#4 Interact with your database

macOS

Start Postico. You should see all your databases listed.

Let's create a new database for ourselves.

Click on the +Database button and add a database called techladies.

You should now see a new database in your view (use the refresh button if you don't). Double-click on the created database to view the contents of your database.

Now, we'll add a table to our database.

Click on the +Table button to add a table and populate it with some data.

Windows

Start pgAdmin. You should see a database server listed on the left hand panel. By default it is named PostgresSQL 12.

Double click on it and enter the password if prompted. You would have set this password some time during or after the installation of pgadmin.

Right click on Database and click Create > Database. In the window, give your database a name.

Expand the name of your database and open schemas > public, then right click on Tables and click Create > Table.

In the General tab, give the table a name, and under the Columns tab, click the + button to add a column. You can give it any name, and you can choose character varying for the Data Type.

Right click on your table in the left panel navigation, and click Scripts > INSERT Script. In the text editor on the right, replace the ? with some data.

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Bravo! You now have your own database with some data! 🎉 🎉 😁

Additional Task

Try out a few SQL queries to query data in your new table!