Vue.js for beginners

Ehab-24 — Tue, 04 Apr 2023 10:00:39 +0000

Introduction

This tutorial is a starting point for anyone getting started with Vuejs.

Prerequisites

You will need a nodding acquaintance with the basics of Vue such as v-on, v-bind, refs etc. Please refer to the official documentation for Vue.js if you feel unfimiliar with a terminology at any point.

Topics

Following are the topics we will be taking a look at:

Single File Components
Props and Events
Routing
Composables

Source Code

To follow along with the tutorial, you can find the source code here.

Setup

For a better developer experience, we will be using vite along with tailwindcss.

How to install?

To get started with vite and tailwind, simply follow the official guide.

Cleanup

Navigate to my-project/src and remove the everything except for main.js, style.css and App.vue files.
Remove everything in App.vue, we will come back to it in a minute.

Single File Components

A single file component (SFC) is a special file format that allows us to encapsulate the template, logic and styling of a Vue component in a single file. These files are named as *.vue, where * is the name of component in UpperCamelCase.

Constraints

A Vue SFC must have atleast one <sricpt> or <template> tag. However, Vue will give a warning if no <template> tag is provided to an SFC.

Example

Create a new folder in the src directory and name it components. Create a new file in src/components with the name Oven.vue.

What is happening?

We bind the disabled property of <button> to the isBusy ref. Any time the value of isBusy changes, our button will listen to the change and re-render (if needed).
We also provide a listener v-on:click or @click to the <button> component and assign it a handler function. This handler is executed every time the button is pressed.

Add the oven to App.vue and test it.

Views

Views in Vue are exactly the same as Vue components. The components that act as views or pages for routing are referred to as views.

Example

Create a new folder in the src directory and name it views.
Add a new file in src/views with the name Kitchen1.vue.

Our kitchen only contains a single oven for now.

Let's also update the App.vue file:

Props

Props are attributes that are passed to a Vue SFC via the parent component. They can be declared using the defineProps macro when using <script setup>. This function returns an object containing all the passed props.

Receiving props

Let's change the oven component to bake whatever we want instead of just a cake.

We will also need to change the bakeACake function and prompt logic.

Passing props

I say we bake a banana bread this time.

Go to views/Kitchen1.vue and pass food and duration props to the oven.

Notice that we pass banana bread as a static string but bind the duration property to 3000 even though it is static. This is because we need to tell Vue that this a Javascript expression (a number in our case) instead of a string.

Let's see how it works:

Events

What if our kitchen had multiple ovens to bake different food items and we wanted to keep track of all the items currently being baked?

Solution

Create multiple ovens.
Add to 'currentlyBaking' when an oven is started.
Listen to the event when a food item is baked and remove it from the currentlyBaking list.

Create multiple ovens

Navigate to views/Kitchen1.vue and initialize a constant list ovens

Now replace the <Oven /> tag with a v-for directive that will render the ovens list.

Emitting events

We need our oven to tell the kitchen when it starts baking an item as well as when it finishes. To accomplish this task, we will simply emit events from the oven component.
Navigate to components/Oven.vue and define start and baked events using the defineEmits macro.

Let's also emit these events using the emit function.

Listening to events

Now that our ovens are able to communicate their status with the parent component, the only thing that is left to do is to listen to their events.

Navigate to views/Kitchen1.vue and add the following logic:

The currentItems list is what we want to render to the screen. This can be easily achieved using the v-for directive, just like we did for the ovens list.

We assign addToCurrentItems and removeFromCrrenltItems handler to the start and baked events respectively.

Now if we run the app, our kitchen will have all the info it needs.

Routing

A single kitchen won't be able to cope with a high number of orders. So let's add two more.

Navigate to src/views and two files Kitchen2.vue and Kitchen3.vue. Kitchen2 is just like Kicthen1 while Kitchen3 is under maintenance and is inaccessible.

But how do we navigate between all these rooms? I hear you ask. Well, the answer is simple:

Define all routes
Create a router
Add a navbar
Assign it to the app component

Define route options

Create a new folder router inside src and create an index.js in src/router.

Here, we define an array routes containing the navigation options for each route (or kitchen).

Creating a router instance

Creating a router instance is simple:

What is happening?

We define a vue router instance using the createRouter macro which takes in a history mode as well as an array of route options. A route option simply needs a path, an optional name (this is useful for named routes. See named routes for more detail), and a component to render, where the component is a view.

Adding a Navbar

We also need a NavBar to easily navigate between the kitchens.
Create a new file NavBar.vue in the components directory and use the <router-link> tag to create navigation links.

<router-link> acts like a <a> tag however, it has several benefits.

This allows Vue Router to change the URL without reloading the page, handle URL generation as well as its encoding.

Using the router

Navigate to src/main.js and alter your code to match the following:

But how does the 'App' component know where to render these components (views)? Well, we tell it of course.
Head over to src/App.vue and add a <router-view> tag inside the template.

Our restaurant is looking clean and we can easily navigate between the kitchens.

What about kitchen3?

You forgot didn't you? Kitchen3 is barred! and you can not enter it.
In order to block all entrances, we need to intercept calls made to the router. This can be easily done by using a navigation guards known as router.beforeEach.

Head over to router/index.js, and add the following code:

What is happening?

The router.beforeEach is called every time we make a navigation call to the router. Here, we have access to to and from routes and we may explicitly return false to cancel the navigation.

Composables

You may have noticed that we duplicated all our code logic from Kitchen1.vue to Kitchen2.vue, which of course, is not ideal. And that is where we use composables.

a "composable" is a function that leverages Vue's Composition API to encapsulate and reuse stateful logic.

Key points

They become more and more vital as the code base scales.
In addition to reusability, composables also provide readablity.
I usually give each composable file the same name, in lowerCamelCase, as the function it exports.

Extracting reusable code

Create a new folder in the src directory with the name of composables and add new file getCurrentKitchenItems. Define a function with the same name that encapsulates the logic for items that are currently being baked.

Now in both of our functioning kitchens, we can do:

Much cleaner! And our kitchens work smoothly as well.

Behind the scenes, I also added a CoffeeMaker component (which works just like an Oven).
You can imagine how our code would bloom up, had we not used composables.

Wrap up

And with this, our little session comes to an end. You can keep adding more and components and custom logic to this project. The benefit of following Vue's conventions is that your code base is highly scalable.

Just remember to take it one step at a time, and keep finding motivation.

HAPPY LEARNING!!!

DEV Community: Ehab-24

Vue.js for beginners

Introduction

Prerequisites

Topics

Source Code

Setup

How to install?

Cleanup

Single File Components

Constraints

Example

What is happening?

Views

Example

Props

Receiving props

Passing props

Events

Solution

Create multiple ovens

Emitting events

Listening to events

Routing

Define route options

Creating a router instance

What is happening?

Adding a Navbar

Using the router

What about kitchen3?

What is happening?

Composables

Key points

Extracting reusable code

Wrap up