Express.js Study Note: Route Order Is Matters!

Last post, I have learned to develop my first Express App from the course. Basically, it has three routes. When we type "/", "/bye" and "/cat", the app will receive the request and send the matched response to us.

But, if we want to send a nice message when users type other texts after slash, what should we do?

We can write a "*" route which will run whenever out app gets any request to any url aside from those three routes that we have already defined.

app.get("*", function)

In the App.js file, we add a new star route, and it will send you a new message whenever you type any undefined request.

I run my app, and put some random texts after slash, and hit enter. All I get is "You are a star!".

If we move the star route to the top of those three routes, what will happen? The instructor run the app, the result is even though we send the "/", "/bye" or "/cat" request, all we get is "You are a star".

Therefore, the order of route is matters!

If we put the star route at first, nothing else will be matched ever. The key concept is that the first route that matches a given request is the only route that will be run. That's why we normally put the start route at the bottom.

Another thing I learned is route parameters.

Image if we have a blog which covers a lot of subjects, it would be super stress to cover every single subject in app.get. The code will not DRY(don't repeat yourself), and it wastes a lot time. The most importantly, we will never match all subjects that users want to search.

To solve the above problem, we need to use route parameter which we can use to define a pattern in a route that doesn't have to be matched word for word. It just needs to match the same patterns.

For example, I write a route pattern:

app.get ("/a/:subName, function)

The ":subName" is the pattern. Users can type "/a/anyname" to send the request, and receive the relevant message.

When I type "/a/babywipe" in the url to make a request, I will receive the new message.

We can also add more "/:patterns" in the app route too. For example, we can add "/:id/:title/" after the comments.

As the result, when I type the "/a/babywipe/comments/123/best_baby_wipe" which matches the pattern route, the app send "Leave Your Comment Here" message back to me.

Comments

Intermediate Express.js: How To Add Styles & Partials in EJS File?

So far, we only have simple HTML tags and ejs tags in each ejs file. Every template page has no style at all. And the basic HTML header and footer are also missing. Today, I learned how to add styles and partials in ejs file. Link Style Step One: Touch a Separate CSS file I create a new directory "Style" under the "EJSDemo" directory, then I add a new CSS file "app.css" inside "Style" folder. Step Two: Add app.use(express.static()) in the app.js I add app.use(express.static("style")) in the "app.js". This will tell Express.js to serve the content of "Style" directory. Step Three: Write styles in CSS file I simple give body an orange background color and set text color to be grey. Step Four: Link to CSS file in the EJS file I just add <link> tag to link the "app.css" file on the top of the h1 tag in each ejs template. As the result, when I run the app and...

Seven Most Common jQuery Methods Last Part: ADD/REMOVE/TOGGLE CLASS()

Add, remove and toggleClass is also a very common way to manipulate style. .addClass() and .removeClass() I add two class selector in the style tag. Class one is to change text color to be green, and class two is change both text and background color. Now I refresh the page and change h1 text to green by using addClass() method: $("h1").addClass("one") . If you want to remove the style, you can change it to removeClass("one"). I do the same thing to the list. I change the list color and add a background color by adding the class two style value: $("li").addClass("two") . .toggleClass() According to jQuery, toggerClass method can add or remove one or more classes from each element in the set of matched elements, depending on either the class's presence or the value of the state argument. I only want to change the first list item color and background by writing: $("li").first().toggleClas...

My Story: A Mommy Start To Learn Code From Zero

From Google Image I am not a programmer, and I thought I would never become one. Everytime I see someone is coding, I think he or she must be very talent. For me, coding is a very difficult subject to learn. Not only the language has so many rules, but also the logical reasoning behind the language is complex. In my graduated school, I knew many friends who didn't have any coding background, but they are doing programmer or developer jobs now. Some of them went to school to study coding, and some of them learned to code by themselves. Their stories are so impressive. I wasn't ready to learn code until I finished my first Chinese book "留学，我的青春呀!" recently. I always want to be a writer and write my own book. I started writing blog three years ago, and I updated my post two to three times every week. As I enjoyed writing , I started to get some followers, likes, and good comments on my blog. Then, I decided to plan my first book. My First...

Learn Bootcamp From Zero

Search This Blog