Free Code Camp and Learning Express.js: Jade

Here’s the third lesson in the Express.js tutorial.  As always, there are a couple sneaky things, but overall, this isn’t that difficult.

 

NOTE:  I found this blog post to be quite helpful for this lesson:

http://webapplog.com/jade-handlebars-express/

Let’s start with the Directions and Hints:

JADE
 Exercise 3 of 8
Create an Express.js app with a home page rendered by Jade template engine.
The homepage should respond to /home.
The view should show the current date using toDateString.
——————————————————————————-
## HINTS
The Jade template file index.jade is already provided:
    h1 Hello World
    p Today is #{date}.
This is how to specify path in a typical Express.js app when the folder is ‘templates’:
    app.set(‘views’, path.join(__dirname, ‘templates’))
However, to use our index.jade, the path to index.jade will be provided as process.argv[3].  You are welcome to use your own jade file!
To tell Express.js app what template engine to use, apply this line to the Express.js configuration:
    app.set(‘view engine’, ‘jade’)
Instead of Hello World’s res.end(), the res.render() function accepts a template name and presenter data:
    res.render(‘index’, {date: new Date().toDateString()})
We use toDateString() to simply return the date in a human-readable format without the time.
——————————————————————————-
## NOTE
When creating your projects from scratch, install the jade dependency with npm.

Again, the port to use is passed by expressworks to the application as process.argv[2].

The second to last line tells us that Jade is a package and that we need to install it via the npm (Node Package Manager).  Here’s how we do that, and the ugly results we get back…

$ npm install jade
npm WARN package.json chat-example@0.0.0 No repository field.
npm WARN package.json chat-example@0.0.0 No license field.
npm WARN deprecated jade@1.11.0: Jade has been renamed to pug, please install the latest version of pug instead of jade
npm WARN deprecated transformers@2.1.0: Deprecated, use jstransformer
jade@1.11.0 node_modules/jade
├── commander@2.6.0
├── character-parser@1.2.1
├── void-elements@2.0.1
├── jstransformer@0.0.2 (is-promise@2.1.0, promise@6.1.0)
├── mkdirp@0.5.1 (minimist@0.0.8)
├── constantinople@3.0.2 (acorn@2.7.0)
├── with@4.0.3 (acorn@1.2.2, acorn-globals@1.0.9)
├── clean-css@3.4.13 (commander@2.8.1, source-map@0.4.4)
├── transformers@2.1.0 (promise@2.0.0, css@1.0.8, uglify-js@2.2.5)

└── uglify-js@2.6.2 (uglify-to-browserify@1.0.2, source-map@0.5.6, yargs@3.10.0)

We’ll start with the variables.  Note that they tell us that, as before, the port and filePath will be supplied in process.argv.

var express = require('express');
var path = require('path');
var port = process.argv[2];
var filePath = process.argv[3];

var app = express();

 

We also know that we are going to listen on a port, and they give us two app.set() statements as well, giving us:

var express = require('express');
var path = require('path');
var port = process.argv[2];
var filePath = process.argv[3];

var app = express();

app.set('views', path.join(__dirname, 'templates'));
app.set('view engine', 'jade');

app.listen(port);

Finally, we’re serving a page, so we need an app.get() function, inside of which will be the page we are “rendering”.  They give us this render statement, too, and so we have:

var express = require('express');
var path = require('path');
var port = process.argv[2];
var filePath = process.argv[3];

var app = express();

app.set('views', path.join(__dirname, 'templates'));
app.set('view engine', 'jade');

app.get('/', function(req, res) {
  res.render('index', {date: new Date().toDateString()})
})

app.listen(port);

 

And………..it doesn’t work.  It keeps saying “cannot get /home”.  Yeah, I hate when I can’t get home too.  Okay, so I thought this would be an easy fix.  Remembering the first lesson, I changed the ‘/’ in the app.get statement to ‘/home’ and ran it again.

Still didn’t work.

I was a little frustrated now.  What had I missed?  I read and reread the instructions.  Then I caught it – I hadn’t used the filePath variable anywhere, so the program didn’t know where to look for the Jade file.  But the question was, where do I use it?

 

Well, see that app.set() with the path.join statement?  That looked awfully familiar from the Static exercise, where we used:

app.use(express.static(process.argv[3]||path.join(__dirname, 'public')));

 

So, I added “process.argv[3]||” to my app.use() statement and, lo and behold, the program passed!  Here’s the final program, for reference:

var express = require('express');
var path = require('path');
var port = process.argv[2];
var filePath = process.argv[3];

var app = express();

app.set('views', process.argv[3]||path.join(__dirname, 'templates'));
app.set('view engine', 'jade');

app.get('/home', function(req, res) {
  res.render('index', {date: new Date().toDateString()})
})

app.listen(port);

See you next time!

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