Nodejs

Intall and Hello world.

Install Node.js on Centos 8.

# dnf -y install nodejs

Create the projects folder.

$ mkdir -p ~/projects/exapmles-nodejs

Create ‘Hello World from Node.js’ project.

$ mkdir ~/projects/examples-nodejs/hello_world
$ touch ~/projects/examples-nodejs/hello_world/hello_world.js

Edit hello_world.js file.

console.log('Hello World from Node.js');

Run your Hello world project.

$ node ~/projects/exapmles-nodejs/hello_world/hello_world.js
Hello World from Node.js

Edit hello_world.js once again.

// something like python f-string
console.log(`Hello World from Node.js ${process.version}`);

Then run.

$ node ~/projects/exapmles-nodejs/hello_world/hello_world.js
Hello World from Node.js v10.21.0

As you can see, Node.js has its own analog of python f-strings.

let foo='bar';
console.log(`the 'foo' is '${foo}'`);

The code shown before, in python will be:

foo='bar'
print(f"the 'foo' is '{foo}'")

nodeenv the virtualenv analog for Node.js

Install

$ workon shmakovpn
$ pip install nodeenv
$ nodeenv --version
1.5.0

Get a list of available versions of Node.js.

$ nodeenv --list
...
14.11.0

Create your first Node.js environment into current virtualenv (-p flag).

$ nodeenv -v 14.11.0 -p
$ which node
~/.virtualenvs/shmakovpn/bin/node
$ node --version
v10.21.0
$ ~/.virtualenvs/shmakovpn/bin/node --version
v14.11.0

Reactivate your virtualenv.

Typescript Hello World

We will use Node.js with nodeenv and virtualenv.

Activate virtualenv.

$ workon shmakovpn
$ node --version
v14.11.0
$ which npm
~/.virtualenvs/shmakovpn/bin/npm

Install typescript.

Note

If you use Ubuntu and work behind proxy, you may need to set NODE_EXTRA_CA_CERTS environment variable to fix UNABLE_TO_GET_ISSUER_CERT_LOCALLY error of npm.

export NODE_EXTRA_CA_CERTS="/etc/ssl/certs/ca-certificates.crt"

$ npm install -g typescript
/home/shmakovpn/.virtualenvs/shmakovpn/bin/tsc -> /home/shmakovpn/.virtualenvs/shmakovpn/lib/node-modules/typescript/bin/tsc
/home/shmakovpn/.virtualenvs/shmakovpn/bin/tsserver -> /home/shmakovpn/.virtualenvs/shmakovpn/lib/node-modules/typescript/bin/tsserver
+ typescript@4.0.2
added 1 package from 1 contributor in 2.351s
$ npm list -g | grep typescript
└── typescript@4.0.2
$ tsc -v
Version 4.0.2

Create file ~/projects/examples-nodejs/hello_typescript.ts.

$ touch ~/projects/examples-nodejs/hello_world/hello_typescript.ts

const myName: string = 'Me';
console.log(`Hello ${myName}`);

Let’s compile hello_typescript.ts

tsc ~/projects/examples-nodejs/hello_world/hello_typescript.ts

tsc will create hello_typescript.js file

var myName = 'Me';
console.log("Hello " + myName);

Highlight typescript code in vim.

todo