To use HTML as the view engine in Node.js Express, we use the express.static middleware.
For instance, we write
app.use(express.static(__dirname + "/public"));
to make the /public folder in the project folder a static file directory.
Then we can put HTML files in there and open them directly.
To load and execute external JavaScript file in Node.js with access to local variables, we create a module with the variables and require the module.
For instance, we write
const PI = 3.14;
exports.area = (r) => {
return PI * r * r;
};
exports.circumference = (r) => {
return 2 * PI * r;
};
in circle.js to export the area and circumference functions.
Then we write
const circle = require("./circle");
console.log(circle.area(4));
to require the circle.js file and call the area function from circle.js.
To change value of process.env.PORT in Node.js, we set the PORT variable.
For instance, we run ‘
$ PORT=1234 node app.js
from Unix or Linux to set the PORT environment variable to 1234 before running app.js.
We can do the same thing with
$ export PORT=1234
$ node app.js
On Windows, we run
set PORT=1234
to set the port.
And on Windows PowerShell, we run
$env:PORT = 1234
to do the same thing.
To use the Underscore module with Node.js, we call require to include the underscore module.
For instance, we write
const _ = require("underscore");
to import the underscore module in our JavaScript code to use its functions.
To install Node.js nvm in Docker, we run curl to install it.
For instance, in our dockerfile, we add
SHELL ["/bin/bash", "--login", "-c"]
RUN curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash
RUN nvm install 10.15.3
to run curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bash
to download the nvm install script and run bash to install it with the downloaded script.
And then we run
nvm install 10.15.3
to install nvm 10.15.3.