Lesson 1: Introduction to Vue 3 and Project Setup

Welcome to the first lesson in our course, "Learn how to set up and build a minimal project using Vue 3 and JavaScript." In this lesson, we will introduce Vue 3 and guide you through the initial setup of a minimal Vue 3 project.

What is Vue.js?

Vue.js is a progressive JavaScript framework used to build user interfaces. It is designed to be incrementally adoptable and focuses on the view layer only. This makes integrating it into projects a breeze. Vue can also be used to power single-page applications (SPAs) when combined with modern tooling and supporting libraries.

Key Features of Vue 3:

• Reactivity System: Vue's reactivity system automatically updates the DOM when your application state changes.
• Composition API: Provides a set of additive, function-based APIs that allow for more flexible code organization.
• Improved Performance: Enhanced rendering and memory usage.
• TypeScript Support: Built-in optimizations and TypeScript support out of the box.

Prerequisites

Before you start, ensure you have the following installed:

• Node.js (version 12.x or above)
• npm or yarn (Node package managers)

You can download the latest version of Node.js here.

Setting Up Your Vue 3 Project

With the prerequisites out of the way, let's set up a new Vue 3 project.

Step 1: Install Vue CLI

First, you need to install the Vue CLI (Command Line Interface) globally on your machine. Vue CLI provides a simple way to create and manage Vue projects.

npm install -g @vue/cli

Step 2: Create a New Vue 3 Project

Once Vue CLI is installed, you can create a new Vue project. Open your terminal and run the following command:

vue create my-vue-app

You'll be prompted to choose a preset. Select the default preset to keep things simple for now.

Step 3: Navigate to Your Project Directory

After the CLI has finished setting up your project, navigate to your new project's directory:

cd my-vue-app

Step 4: Start the Development Server

Now, let's run the development server to see if everything is set up correctly:

npm run serve

Open your web browser and navigate to http://localhost:8080. You should see the default Vue 3 application running.

Project Structure

Let's take a quick look at the project structure generated by Vue CLI:

my-vue-app/
├── node_modules/
├── public/
│   ├── index.html
│   └── ...
├── src/
│   ├── assets/
│   ├── components/
│   ├── App.vue
│   ├── main.js
├── .gitignore
├── package.json
├── README.md
└── ...

Key Files and Directories:

• public/: Contains static assets like index.html.
• src/: Primary directory for your app's source code.
• App.vue: The root component.
• main.js: The entry point of your application.

Adding a New Component

Let's add a simple component to understand how Vue components work.

Step 1: Create a New Component File

Inside the src/components directory, create a file named HelloWorld.vue with the following content:

<template>
  <div>
    <h1>{{ message }}</h1>
  </div>
</template>

<script>
export default {
  name: 'HelloWorld',
  data() {
    return {
      message: 'Hello, Vue 3!'
    }
  }
}
</script>

<style scoped>
h1 {
  color: #42b983;
}
</style>

Step 2: Use the Component in App.vue

Open the App.vue file and update it to use the new HelloWorld component:

<template>
  <div id="app">
    <HelloWorld/>
  </div>
</template>

<script>
import HelloWorld from './components/HelloWorld.vue'

export default {
  name: 'App',
  components: {
    HelloWorld
  }
}
</script>

Conclusion

Congratulations! You've successfully set up a Vue 3 project and added a new component. In this lesson, we covered:

• An introduction to Vue.js and its features.
• Setting up Vue CLI and creating a new Vue 3 project.
• Understanding the project structure.
• Creating and using a new Vue component.

In the next lesson, we will dive deeper into Vue's reactivity system and learn more about data binding.

Happy coding!

Lesson 2: Creating and Understanding Vue 3 Components

Introduction

In this lesson, we will focus on creating and understanding Vue 3 components. Components are the building blocks of a Vue.js application. They help to encapsulate reusable code, making your application more maintainable and scalable. By the end of this lesson, you will be adept at creating simple to complex Vue 3 components and understand their properties and lifecycle methods.

Basic Structure of a Vue Component

A Vue component typically consists of three sections:

• Template: Defines the HTML structure of the component.
• Script: Contains the JavaScript code for the component.
• Style: (Optional) Contains the CSS styles specific to the component.

Here is a basic example of a Vue component:

<template>
  <div class="counter">
    <p>{{ message }}</p>
    <button @click="increment">Increment</button>
    <p>Count: {{ count }}</p>
  </div>
</template>

<script>
export default {
  name: 'CounterComponent',
  data() {
    return {
      message: 'Hello, this is a Vue 3 component!',
      count: 0
    };
  },
  methods: {
    increment() {
      this.count++;
    }
  }
};
</script>

<style scoped>
.counter {
  margin: 20px;
}
button {
  cursor: pointer;
}
</style>

Understanding Component Properties

Template Section

The <template> section is where the HTML structure for the component is defined. This section can contain data bindings, loops, conditionals, and events.

Script Section

The <script> section defines the JavaScript logic for the component. Let's break it down:

• name: The name of the component, which is useful for debugging.
• data(): A function that returns an object containing the component's reactive data properties.
• methods: An object containing the methods that can be used within the template and are typically bound to user events (e.g., button clicks).

Style Section

The <style> section defines the styles specific to the component. The scoped attribute ensures that the styles are applied only to the respective component, not globally.

Props: Passing Data to Child Components

Props allow you to pass data from a parent component to a child component. This is crucial for building hierarchical and modular UIs.

Parent Component

<template>
  <div>
    <MessageComponent :message="parentMessage" />
  </div>
</template>

<script>
import MessageComponent from './MessageComponent.vue';

export default {
  name: 'ParentComponent',
  components: {
    MessageComponent
  },
  data() {
    return {
      parentMessage: 'Hello from the Parent Component!'
    };
  }
};
</script>

Child Component

<template>
  <div>{{ message }}</div>
</template>

<script>
export default {
  name: 'MessageComponent',
  props: {
    message: {
      type: String,
      required: true
    }
  }
};
</script>

Component Lifecycle Hooks

Vue components come with several lifecycle hooks that allow you to perform actions at different stages of the component lifecycle. The most commonly used hooks are:

• created(): Called after the instance is initialized.
• mounted(): Called after the component is mounted onto the DOM.
• updated(): Called after the component is updated.
• destroyed(): Called after the component is destroyed.

Example Using Lifecycle Hooks

<template>
  <div>
    <p>Component has been mounted for: {{ seconds }} seconds</p>
  </div>
</template>

<script>
export default {
  name: 'TimerComponent',
  data() {
    return {
      seconds: 0
    };
  },
  created() {
    console.log('Component Created');
  },
  mounted() {
    console.log('Component Mounted');
    this.timer = setInterval(() => {
      this.seconds++;
    }, 1000);
  },
  destroyed() {
    console.log('Component Destroyed');
    clearInterval(this.timer);
  }
};
</script>

Summary

This lesson covered the core aspects of creating and understanding Vue 3 components. We delved into the structure of a Vue component, including the template, script, and style sections. We explored the concept of props for passing data between components and introduced lifecycle hooks for managing component state at different stages. These skills lay the foundation for building complex, maintainable Vue.js applications.

In the next lesson, we will explore more advanced topics, such as component communication methods (e.g., custom events, event buses) and dynamic components.

Lesson #3: Using Vue Directives and Data Binding

Welcome to Lesson #3: Using Vue Directives and Data Binding. By now, you should be familiar with the basics of Vue 3 and understanding its components. In this lesson, we'll dive deeper into the core concepts of directives and data binding in Vue, which are essential for dynamic and interactive applications.

Directives in Vue

Directives are special tokens in the markup that tell the library to do something to a DOM element. Vue provides several built-in directives that you can use to manipulate the DOM.

• v-bind: Dynamically bind an attribute to an expression.
• v-model: Create a two-way binding on a form input element.
• v-if, v-else, v-else-if: Conditionally render elements.
• v-for: Render elements based on an iteration over a list.

Example of Using v-bind

When you want to bind the href attribute of a <a> tag to a data property:

<a v-bind:href="url">Link</a>

export default {
  data() {
    return {
      url: 'https://vuejs.org'
    };
  }
};

Example of Using v-model

When you want to create a two-way binding with an input field:

<input v-model="message">
<p>The message is: {{ message }}</p>

export default {
  data() {
    return {
      message: ''
    };
  }
};

Conditional Rendering with v-if

The v-if directive is used to conditionally render an element based on a bool expression. Here's an example:

<div v-if="isVisible">Visible Content</div>
<div v-else>Hidden Content</div>

export default {
  data() {
    return {
      isVisible: true
    };
  }
};

List Rendering with v-for

To render a list of items, you use the v-for directive. This allows you to iterate over an array and render a block of elements for each item:

<ul>
  <li v-for="item in items" :key="item.id">{{ item.text }}</li>
</ul>

export default {
  data() {
    return {
      items: [
        { id: 1, text: 'Item 1' },
        { id: 2, text: 'Item 2' },
        { id: 3, text: 'Item 3' }
      ]
    };
  }
};

Data Binding

Data binding in Vue.js is a powerful feature that allows you to create highly dynamic and interactive user interfaces. There are two primary types of data binding:

1. One-Way Data Binding: Data flows in one direction, from the model to the view.
2. Two-Way Data Binding: Data flows in both directions, between the model and the view.

One-Way Data Binding

In Vue, the curly braces {{ }} are used to bind data from the model to the view:

<p>{{ message }}</p>

export default {
  data() {
    return {
      message: 'Hello, Vue!'
    };
  }
};

Two-Way Data Binding

Two-way binding is often used in forms. The v-model directive binds the value of form input elements with the data properties:

<input v-model="message">
<p>The message is: {{ message }}</p>

export default {
  data() {
    return {
      message: ''
    };
  }
};

Summary

In this lesson, we explored the vital concepts of Vue directives and data binding. Directives allow us to manipulate the DOM dynamically with built-in functionality like v-bind, v-model, v-if, and v-for. Data binding, on the other hand, helps sync data between the model and the view, enabling us to create interactive and dynamic user interfaces.

Feel free to experiment with these features in your Vue applications to get a better understanding. In the next lesson, we will dive into Vue's reactivity system to understand better how Vue manages data changes and updates the DOM efficiently. Happy coding!

Lesson 4: Routing with Vue Router

Overview

In this lesson, we will explore how to navigate between different views in a Vue 3 application using Vue Router. Vue Router is the official routing library for Vue.js, allowing developers to establish multi-page applications with ease.

Table of Contents

1. Introduction to Routing
2. Setting Up Vue Router
3. Defining Routes
4. Navigation Methods
5. Route Parameters
6. Nested Routes
7. Navigation Guards

1. Introduction to Routing

Routing is essential in any single-page application (SPA). It enables users to navigate to different parts of your application without refreshing the page. Vue Router provides a robust way to define routes and manage navigation.

2. Setting Up Vue Router

Before using Vue Router, ensure it is installed in your Vue 3 project. Since this course skips setup steps, ensure Vue Router is already integrated.

import { createRouter, createWebHistory } from 'vue-router';

// Components
import Home from './components/Home.vue';
import About from './components/About.vue';

// Define routes
const routes = [
  { path: '/', component: Home },
  { path: '/about', component: About }
];

// Create router instance
const router = createRouter({
  history: createWebHistory(),
  routes
});

export default router;

3. Defining Routes

Routes are defined in an array of objects where each object represents a single route configuration. Here's an example:

const routes = [
  { path: '/', component: Home },
  { path: '/about', component: About }
];

• path: URL path.
• component: Component tied to the route.

4. Navigation Methods

Vue Router provides multiple ways to navigate between routes, including link components and programmatic navigation.

Using <router-link>

<template>
  <div>
    <router-link to="/">Home</router-link>
    <router-link to="/about">About</router-link>
  </div>
</template>

Programmatic Navigation

Programmatic navigation is useful for condition-based navigation.

methods: {
  goToAbout() {
    this.$router.push('/about');
  }
}

5. Route Parameters

Route parameters allow dynamic segments in routes, often utilized in detail views.

Defining Route with Parameters:

const routes = [
  { path: '/user/:id', component: User }
];

Accessing Parameters in Component:

export default {
  setup() {
    const route = useRoute();
    const userId = computed(() => route.params.id);
    return { userId };
  }
}

6. Nested Routes

Nested routes enable a parent-child route relationship, suitable for dashboards with sub-sections.

Defining Nested Routes:

const routes = [
  { 
    path: '/user/:id', 
    component: User,
    children: [
      { path: 'profile', component: UserProfile },
      { path: 'posts', component: UserPosts }
    ]
  }
];

Using <router-view> for Nested Routes:

<template>
  <div>
    <router-view></router-view>
  </div>
</template>

7. Navigation Guards

Navigation guards enable you to perform checks before navigating to or from a route.

Global Before Guards:

router.beforeEach((to, from, next) => {
  if (to.path !== '/login' && !isAuthenticated) {
    next('/login');
  } else {
    next();
  }
});

Route-Specific Guards:

const routes = [
  { 
    path: '/dashboard',
    component: Dashboard,
    beforeEnter: (to, from, next) => {
      if (!isAuthenticated) next('/login');
      else next();
    }
  }
];

---

End of the Lesson.

This covers the foundational aspects of routing with Vue Router in a Vue 3 application. Understanding these concepts allows you to build robust and navigable SPAs. In the next lesson, we'll delve into Vuex for state management. Happy coding!