VueJS basics

his is the second part in a series of articles I am writing about how I used VueJS to build a static site.

Assumptions for this article

  • You have NodeJS 8.x installed with npm.
    • You can verify your installation by running these commands in a PowerShell window,
node --version
npm --version
  • You have some knowledge of CLI-based bootstrapping, and development.
  • You are using some sort of a web development IDE. I highly recommend VS Code.

Setup

You’ll want to get the official Vue CLI first. Be sure to install the latest stable release of the CLI. There is a beta version out there. At the time of this writing, 3.0 is still in beta so you can refer to the README for the 2.x version on the master branch. Then, run:

npm install -g vue-cli
vue init webpack my-project

Go through the prompts in your shell and complete the boilerplate project setup. These are my settings:

? Project name static-site
? Project description A Vue.js project
? Author Blog Author <author@blog.com>
? Vue build runtime
? Install vue-router? Yes
? Use ESLint to lint your code? Yes
? Pick an ESLint preset Standard
? Set up unit tests Yes
? Pick a test runner karma
? Setup e2e tests with Nightwatch? Yes
? Should we run `npm install` for you after the project has been created? (recommended) npm

You’ll notice that I used the word webpack in the command to create the project. That’s the name of the webpack template in the CLI. The CLI will automatically create the necessary webpack base configuration with all the loaders, extractors etc.
Once you are done with the setup, you can start-up your dev server for local development using:

npm run dev

You can access the local server using http://localhost:8080. This is it for setup. For most static sites, I don’t anticipate any changes in the base webpack config. So you don’t have to meddle with it at all, not even when you are ready to build a distribution package.

Basics

The sweet spot, in my opinion, for developing using Vue is, its single-file components. Everything that a component needs, the HTML template, the script, and the CSS (or SCSS, if you are living in the 21st century), is in the same file. This encourages you to split your site (or app) into simpler components that do only one thing. It encourages you to use the parent-child communication pattern effectively by way of props.

I won’t go over everything from the excellent documentation on VueJS’ docs site. But I will go over some of the basics, that I think are important before I explain how I built Net Your Problem.

Declarative Rendering

This is just a fancy way of saying, HTML in; HTML out. There is no special language for you to learn here. Of course, this doesn’t do much other than render the view (the HTML).

Open the App.vue file from the project you setup using the CLI and look at the content within the enclosing <template> tag.

and then in main.js:

All this is doing is, creating a new instance of a Vue app, and then binding the app instance to the root view, which is an element with the ID value “app”. As you can see, in App.vue, this is our <div> tag.

OK. But wait. How did Vue know where to look for an HTML element inside the App.vue component. Take a look at the “render” property in the statement for creating a new instance of a Vue app. Its value is an arrow function that accepts a callback function as a parameter. The callback function expects a Vue component to be passed to it. This render function is what kicks-off the render-ing of all child components when you start composing components from the parent component.

Data binding, conditional rendering and loops

A very important building block for any site, application. I am pretty sure almost every single site, web app out there uses conditional rendering and repeated elements all over.

Let’s modify the App.vue like this:

Now, reload the page. You should see the message Hello, World! right below the logo. If you change the value of the showMessage property from true to false, then you should see the message disappear. This was made possible because of the directive v-show. You can read more about conditional rendering and the other directive called v-if. There is an important performance difference between the two.

Let’s add a repeated element. Modify the App.vue’s template contents like this:

If the page hasn’t refreshed, refresh it, and you should see the additions. The condition items.length > 0 is satisfied since the items array has a non-zero size.  We only used a single <li> tag in the template, however, the final result has two of those. That’s because of the v-for directive. You can read more about it in the list rendering section of the guide.

Routers

Web sites, and web apps use URLs to send the user to new sections of a page, or to completely different pages. Routers are used to load/unload components as the user navigates your site/app. Depending on how you structure your site, you may or may not want to use a router at all. It isn’t necessary if you don’t have complex sections in your site, and you don’t need to orchestrate showing and hiding these sections appropriately.

But let’s walk-through it real-quick. If you recall in App.vue, there is a tag called <router-view/>. This is a special tag, which Vue recognizes as the output of a user navigation. That is, when the user navigates somewhere, the Vue system places the content of the new destination in its place.

Have a look at the router/index.js

That is it for some of the basics. I highly recommend reviewing the introduction to Vue’s concepts. You can read about them here.

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