Vue.js Essentials : Reactivity Fundamentals

Vue.js is a popular JavaScript framework for building user interfaces. One of its core features is reactivity, which allows Vue.js to automatically track and update changes in data and adjust the user interface accordingly. Understanding how reactivity works is crucial for developing effective and efficient Vue applications.

In Vue.js, reactivity is achieved through the use of the Vue instance and its built-in reactive properties. When you create a Vue instance, you define a data object that contains the initial values for your application’s data. These values can be accessed and modified using the Vue instance, and any changes made to the data will automatically trigger updates in the user interface.

The reactivity system in Vue.js is based on a dependency tracking mechanism. Whenever a value in the data object is accessed during the rendering process, Vue.js records the relationship between the accessed value and the component that accessed it. This allows Vue.js to know exactly which components are dependent on which data, and update only the necessary parts of the user interface when the data changes.

Vue.js also provides a simple and intuitive syntax for reacting to changes in data. You can use the v-model directive to create two-way data binding between form inputs and data properties, so that any changes in the input value will be automatically reflected in the data, and vice versa. Additionally, you can use computed properties to define complex data transformations that depend on other reactive properties, and watch properties to perform custom actions when specific properties change.

What is Vue.js?

Vue.js is a progressive JavaScript framework that is used for building user interfaces. It is often referred to as a “progressive” framework because it is designed to be incrementally adoptable, meaning you can start using it for small parts of your project and gradually scale it up to a full-fledged application.

Vue.js is often compared to other popular JavaScript frameworks like React and Angular, but it has its own unique features and advantages:

• Easy to understand: Vue.js is known for its simplicity and easy learning curve. It is designed with a minimalistic approach, making it straightforward for developers to understand and use.
• Flexible: Vue.js allows you to build your application in a way that suits your needs. It offers various features and tools that can be combined and customized to match your specific requirements.
• Reactive: One of the key features of Vue.js is its reactivity system. It utilizes a virtual DOM and reactive data-binding to automatically update the user interface whenever the underlying data changes. This makes it easy to build dynamic and responsive applications.
• Component-based architecture: Vue.js encourages the use of reusable and modular components. Components are self-contained and can be easily composed to build complex user interfaces.
• Well-documented: Vue.js has excellent documentation, making it easy for developers to learn and use. The documentation provides detailed explanations, examples, and guides, making it easier for beginners to get started.

Overall, Vue.js is a versatile and powerful framework that provides developers with the tools they need to build modern and interactive user interfaces.

Advantages of using Vue.js

Vue.js is a popular JavaScript framework for building user interfaces. It offers several advantages that make it a preferred choice for many developers. Some of the key advantages of using Vue.js are:

1. Easy learning curve

Vue.js has a gentle learning curve, making it easy for beginners to understand and start building applications. Its syntax is straightforward and similar to plain HTML, CSS, and JavaScript, making it easy to pick up and start using.

2. Lightweight

Vue.js is a lightweight framework, weighing only about 20 KB. This makes it fast to download and easy to incorporate into your projects without affecting the overall performance of your application.

3. Flexible architecture

Vue.js follows a component-based architecture, allowing developers to break down their user interface into reusable and modular components. This makes it easier to manage and maintain code, especially for large-scale projects.

4. Reactive data binding

Vue.js uses a reactive data binding system, which means that any changes in the data are automatically reflected in the user interface. This eliminates the need for manual DOM manipulation and improves development efficiency.

5. Excellent documentation

Vue.js has extensive and well-organized documentation, making it easy for developers to find answers to their questions and learn new concepts. The community surrounding Vue.js is also very active and supportive, providing additional resources and tutorials.

6. Great ecosystem and tooling

Vue.js has a vibrant ecosystem with a wide range of plugins and libraries that can be easily integrated into your project. It also provides excellent tooling, including Vue Devtools for debugging and Vue CLI for scaffolding new projects.

7. Performance

Vue.js is known for its excellent performance, with fast rendering and efficient updates. It uses a virtual DOM system, which optimizes the rendering process and minimizes unnecessary updates.

8. Versatility

Vue.js can be used to build different types of applications, from simple single-page applications to complex enterprise-level projects. It can also be integrated into existing projects without any hassle.

Overall, Vue.js offers a great balance of simplicity, flexibility, and performance, making it a powerful choice for building modern web applications.

Getting Started with Vue.js

What is Vue.js?

Vue.js is a JavaScript framework for building user interfaces. It is designed to be flexible, scalable, and easy to use. Vue.js allows developers to create interactive web applications by providing a powerful core library and a set of optional features and add-ons.

Why Vue.js?

Vue.js has gained popularity among developers for several reasons:

• Simplicity: Vue.js is easy to understand and use, making it a great choice for beginners.
• Reactivity: Vue.js uses a reactive data model, which means that changes to the data are automatically reflected in the user interface.
• Performance: Vue.js is known for its high performance, with fast rendering and minimal overhead.
• Modularity: Vue.js allows developers to use only the features they need, making it highly modular and customizable.

Getting Started

To get started with Vue.js, you need to include the Vue.js library in your HTML file. You can do this by adding the following script tag:

<script src="https://unpkg.com/vue"></script>

Once you have included the Vue.js library, you can create a new Vue instance by calling the new Vue() constructor. This instance will be the root of your application:

var app = new Vue({

// options
})

Vue.js uses a declarative syntax, which means that you define the desired output and Vue.js takes care of updating the DOM to match the desired state. This is done using data properties, which are reactive by default:

var app = new Vue({

data: {
message: 'Hello Vue.js!'
}
})

In the example above, the message property is reactive, which means that whenever it changes, Vue.js will automatically update the corresponding part of the DOM.

Conclusion

Vue.js is a powerful JavaScript framework for building user interfaces. It provides a flexible and scalable solution for creating interactive web applications. With its simplicity, reactivity, performance, and modularity, Vue.js has become a popular choice among developers. Getting started with Vue.js is easy, and with just a few steps, you can start building your own Vue.js applications.

Installing Vue.js

In order to work with Vue.js, you need to have it installed in your development environment. There are several ways to install Vue.js:

Using a CDN

The easiest way to start working with Vue.js is by including it via a Content Delivery Network (CDN). You can do this by adding the following script tag to your HTML file:

<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>

This will include the latest version of Vue.js in your project.

Using npm

If you prefer to manage your dependencies using npm, you can install Vue.js by running the following command in your terminal:

npm install vue

This will install Vue.js and add it as a dependency in your package.json file.

Using the Vue CLI

If you want to take advantage of the full power of Vue.js, including features like hot module replacement, scaffolding, and more, you can use the Vue CLI. To install the Vue CLI, run the following command in your terminal:

npm install -g @vue/cli

This will install the Vue CLI globally on your machine. You can then create a new Vue project by running:

vue create my-app

This will create a new directory called “my-app” and scaffold a new Vue project inside it.

Loading Vue.js in your project

Once you have Vue.js installed, you can start using it by including it in your HTML file:

<script>

new Vue({

el: '#app',

data: {

message: 'Hello Vue!'

}

})

</script>

You can then start building your Vue components and take advantage of Vue.js’s reactivity system.

That’s it! You are now ready to start building Vue.js applications.

Creating a Vue.js Project

Prerequisites

Before creating a Vue.js project, you need to make sure that you have the following prerequisites:

• Node.js: Make sure that Node.js is installed on your machine. You can download it from the official Node.js website and follow the installation instructions.
• Vue CLI: Install Vue CLI globally by running the following command in your terminal:
  npm install -g @vue/cli

Creating a New Vue.js Project

1. Open your terminal and navigate to the directory where you want to create your Vue.js project.
2. Run the following command to create a new Vue.js project with Vue CLI:
   vue create project-name (replace “project-name” with the desired name of your project).
3. Select the preset for your project. You can choose either the default preset or manually select features based on your project requirements.
4. Wait for the project setup to complete. Vue CLI will install all the necessary dependencies and create the project structure for you.
5. Once the project setup is complete, navigate to the project directory using the following command:
   cd project-name
6. Finally, run the following command to start the development server and see your Vue.js project in action:
   npm run serve

Project Structure

When you create a new Vue.js project using Vue CLI, it sets up a standard project structure for you. Here are some important files and directories within the project structure:

• src: This directory contains your application’s source code, including components, styles, and assets.
• public: This directory contains static files that are served as-is, such as the index.html file.
• package.json: This file contains the configuration information and dependencies for your project. You can add or modify dependencies using this file.
• vue.config.js: This file contains the configuration for Vue CLI, including options for building and deploying your project.

Conclusion

Congratulations! You have successfully created a new Vue.js project using Vue CLI. Now you can start building your application by writing Vue components and utilizing the power of Vue.js reactivity.

Reactivity in Vue.js

Reactivity is one of the key features of Vue.js that makes it a powerful framework for building interactive web applications. It allows for automatic updates to the user interface whenever the underlying data changes, without the need to manually manipulate the DOM.

What is Reactivity?

In the context of Vue.js, reactivity refers to the ability of the framework to track changes in data and automatically update the corresponding parts of the user interface. This is achieved through a feature called the “reactivity system”.

The reactivity system in Vue.js uses a combination of JavaScript getters and setters, along with a dependency tracking system, to ensure that the user interface is always up-to-date with the underlying data.

How Does Reactivity Work in Vue.js?

When you define a data property in a Vue component, Vue.js converts it into a reactive property. This means that Vue.js creates a getter and a setter for the property, and also tracks the dependencies of that property.

When a reactive property is accessed in the user interface, Vue.js creates a dependency between the property and the component that accessed it. If the property changes, Vue.js knows which components need to be updated and triggers a re-render of those components.

The Reactivity Caveats

While reactivity in Vue.js is a powerful feature, there are some caveats to keep in mind:

1. Reactivity is limited to properties that are declared in the data option of a Vue component. If you add new properties to an object after it has been created, Vue.js will not be able to track changes to those properties.
2. Reactivity is shallow. This means that Vue.js only detects changes at the top level of the properties. If you modify a nested property, Vue.js will not detect it unless you use the Vue.set() method or the spread operator to create a new object.
3. Reactivity does not work with arrays if you directly modify them using index assignment. Instead, you should use array mutation methods like push() or splice() to make changes to arrays.

Conclusion

Reactivity is a fundamental concept in Vue.js that allows for automatic updates to the user interface based on changes in the underlying data. Understanding how reactivity works and its limitations is important for building robust and efficient Vue.js applications.

Understanding Reactivity in Vue.js

Reactivity is one of the core concepts in Vue.js that allows developers to create dynamic and interactive user interfaces. It refers to the ability of the Vue.js framework to automatically track changes to data and update the DOM accordingly.

How Reactivity Works

When you define data properties in a Vue component, Vue.js automatically creates getters and setters for each property. These getters and setters are responsible for tracking changes to the properties and triggering updates when necessary.

When a property is accessed, Vue.js records the current component as a dependent of that property. This means that if the property changes in the future, Vue.js knows which components need to be updated.

When a property is changed, Vue.js automatically triggers a re-render of the affected components. This re-render only updates the specific part of the DOM that depends on the changed property, resulting in efficient and performant updates.

Reactive Objects and Arrays

Reactivity in Vue.js is not limited to simple data properties. Vue.js also provides reactivity for objects and arrays.

For objects, you can use the Vue.set or vm.$set method to add new properties that are reactive. Similarly, you can use the Vue.delete or vm.$delete method to remove properties from an object.

For arrays, you can use the Vue.set or vm.$set method to add or replace elements at a specific index. The Vue.delete or vm.$delete method can be used to remove elements from an array.

Computed Properties and Watchers

Vue.js also provides additional tools for working with reactive data.

Computed properties allow you to define derived properties that automatically update whenever their dependencies change. Instead of manually updating these properties, Vue.js takes care of updating them automatically.

Watchers allow you to perform logic whenever a specific data property or computed property changes. You can use watchers to run side effects, make HTTP requests, or perform other actions based on the changes in the data.

Conclusion

Understanding reactivity is crucial for developing with Vue.js. It allows you to create dynamic and responsive user interfaces without worrying about manually updating the DOM. By leveraging reactivity, you can focus on building your application’s logic, while Vue.js takes care of the rest.

Data Binding in Vue.js

Introduction

Data binding is one of the key features of Vue.js that allows you to efficiently update and synchronize the data between the model and the view. It enables you to automatically update the user interface whenever the underlying data changes, and also update the data when the user interacts with the UI.

One-Way Data Binding

In Vue.js, one-way data binding is the default mode of data binding. It means that the data flows only in one direction, from the model to the view. The changes in the data will reflect in the view, but any changes made by the user in the view will not affect the model. One-way data binding is achieved by using the double curly braces syntax, {{}}, also known as the mustache syntax, to bind the data to the view.

Two-Way Data Binding

Two-way data binding enables you to establish a bi-directional binding between the model and the view. It means that any changes made to the data by the user in the view will automatically update the model, and vice versa. Vue.js provides two directives, v-model and :value, to achieve two-way data binding. With v-model, you bind an input element’s value to a data property, and any changes made by the user will update the data property. On the other hand, the :value directive allows you to bind the value of an input element to a data property, but you will need to handle the input events manually to update the data.

Computed Properties

Computed properties allow you to dynamically calculate values based on the data properties. They are cached and only re-evaluated when their dependencies change. Instead of directly manipulating the data, you can define computed properties that automatically update when the underlying data changes. Computed properties can be used in the view just like regular data properties, making them convenient for performing complex calculations or filtering data.

Watchers

Watchers allow you to perform asynchronous actions or side effects based on changes in the data. They watch for specific data properties and execute a callback function when the property changes. Watchers are useful when you need to perform complex operations, such as making API requests or updating external libraries, in response to changes in the data.

Conclusion

Data binding in Vue.js is a powerful feature that allows you to effortlessly manage the synchronization between the model and the view. Whether you need one-way data binding or two-way data binding, Vue.js provides flexible options to meet your requirements. Computed properties and watchers further enhance the data binding capabilities, allowing you to perform calculations and handle side effects efficiently.

Components in Vue.js

Components are one of the most powerful features of Vue.js. They allow you to create reusable, self-contained pieces of code that can be easily used and manipulated in your application.

What is a Component?

In Vue.js, a component is a Vue instance with pre-defined options and properties. It encapsulates HTML templates, CSS styles, and JavaScript logic into a single entity, making it easy to reuse and manage.

Benefits of Using Components

Components offer several benefits in Vue.js development:

• Reusability: Components can be reused in different parts of the application, reducing duplicate code and enabling a more modular code structure.
• Maintainability: Components make it easier to manage and update specific parts of an application without affecting the rest of the codebase.
• Organized Structure: Components promote a highly organized structure, allowing developers to easily locate and understand different parts of the application.
• Separation of Concerns: Components separate concerns by encapsulating HTML, CSS, and JavaScript code in a single entity, making it easier to identify and modify specific functionality.

Creating Components

In Vue.js, components can be created using the Vue.component method or by defining a component object using the components property within a Vue instance.

Here is an example of creating a component using the Vue.component method:

Vue.component('my-component', {

template: '<div><p>This is my component!</p></div>'
})

In this example, a component called “my-component” is created with a template that contains a simple paragraph element.

Using Components

Once a component is created, it can be used within other components or within the main Vue instance template.

Here is an example of using the “my-component” component within the template of another component:

Vue.component('parent-component', {

template: `
<div>
<h3>Parent Component</h3>
<my-component></my-component>
</div>
`
})

In this example, a component called “parent-component” is created, and within its template, the “my-component” component is used by simply using its tag name <my-component></my-component>.

Conclusion

Components are a fundamental building block in Vue.js development. They provide a modular and reusable way to structure and organize your application code, making it easier to build and maintain large-scale applications.

Creating and Using Components

In Vue.js, components are reusable and self-contained chunks of code that can be used to build complex user interfaces. They encapsulate the HTML, CSS, and JavaScript logic that define a specific functionality or visual element in an application.

Creating a Component

Components in Vue.js can be created by using the Vue.component() method, which takes two parameters: the name of the component and an object that defines its properties, data, methods, and lifecycle hooks. Here’s an example:

“`javascript

Vue.component(‘my-component’, {

// component properties

data() {

return {

message: ‘Hello, Vue.js!’

}

},

methods: {

showMessage() {

console.log(this.message);

}

},

template: `

`

});

“`

In this example, we create a component called “my-component” with a data property called “message”, a method called “showMessage”, and a template that displays the message and a button.

Using a Component

Once a component is created, we can use it in our Vue.js application by including its tag in the HTML markup. Here’s an example:

“`html

“`

In this example, we include the “my-component” tag inside the div with id=”app”. The component will be rendered and its template will be displayed in place of the “my-component” tag.

Passing Data to Components

Components can also accept data from their parent components by using props. Props are custom attributes that can be added to a component tag and then accessed within the component’s definition. Here’s an example:

“`html

“`

In this example, we pass the value of the parentMessage variable to the component’s “message” prop. Inside the component, the prop can be accessed using the “this.message” syntax.

Component Lifecycle Hooks

Vue.js provides several lifecycle hooks that allow us to perform actions at different stages of a component’s lifecycle, such as before it is mounted, before it is updated, or before it is destroyed. These hooks can be defined in the component’s definition and are executed automatically by Vue.js. Here are some examples of lifecycle hooks:

• created: Called when the component is created.
• mounted: Called when the component is inserted into the DOM.
• beforeUpdate: Called before a component is updated.
• destroyed: Called when the component is destroyed.

By using lifecycle hooks, we can perform tasks such as fetching data from an API, initializing third-party libraries, or cleaning up resources when a component is destroyed.

Conclusion

Components are an essential part of building Vue.js applications. They provide a way to encapsulate and reuse code, making our applications more modular and easier to maintain. By creating and using components, we can build complex user interfaces with ease and take advantage of Vue.js’ reactivity system to create dynamic and interactive applications.

Component Communication in Vue.js

Introduction

In Vue.js, components are the building blocks of an application. They can communicate with each other in various ways to exchange data and trigger actions. This plays a crucial role in creating scalable and reusable code.

Component Communication Methods

• Props: This is the simplest and most common way for a parent component to pass data to its child components. The parent component can pass down props (short for properties) as attributes, and the child component can receive and use these props.
• Custom Events: Child components can also communicate with their parent components by emitting custom events. This allows child components to send information or trigger actions defined in their parent component.
• Event Bus: The event bus is a global Vue instance that acts as a central communication hub. It allows components that are not directly related to communicate with each other by emitting and listening to events.
• Reactive props: Vue provides a reactivity system that automatically tracks and updates changes to reactive properties. By using reactive props, components can automatically respond to changes in the data they depend on, without needing explicit communication.
• Vuex: Vuex is a state management pattern and library for Vue.js applications. It provides a centralized store that allows components to access and update data in a predictable way. Vuex is especially useful for managing complex state and enabling communication between different parts of an application.

Choosing the Right Communication Method

When deciding how to communicate between components in Vue.js, it’s important to consider the specific requirements of the project and the complexity of the data flow.

For simple applications with a simple parent-child component hierarchy, props and custom events are often sufficient. They provide a clear and straightforward way to pass data between components.

For larger or more complex applications, the use of an event bus or Vuex can be beneficial. The event bus allows components to communicate more flexibly, while Vuex provides a centralized state management solution that simplifies communication and makes it easier to track and manage changes in the application’s state.

It’s also worth noting that reactive props can be a powerful way to enable dynamic updates in a component without explicit communication. This can be especially useful when working with data that is subject to frequent changes.

Conclusion

Component communication is a fundamental aspect of Vue.js development. By understanding and utilizing the different communication methods available, developers can create more flexible, scalable, and efficient applications.

Choosing the right communication method depends on the specific requirements of the project and the complexity of the data flow. Whether it’s through props, custom events, or more advanced techniques like the event bus or Vuex, Vue.js provides a variety of options for effective component communication.

Directives in Vue.js

Directives are special attributes in Vue.js that allow you to apply dynamic behavior to an element or component. They are prefixed with the “v-” followed by the name of the directive.

Vue.js provides several built-in directives, such as v-if, v-for, v-bind, and v-on. These directives are used to manipulate the DOM, add or remove elements, modify data bindings, and handle events.

v-if

The v-if directive is used to conditionally render or hide an element based on the value of a given expression. If the expression evaluates to true, the element is rendered. If the expression evaluates to false, the element is removed from the DOM.

Example:

<div v-if="isUserLoggedIn">

You are logged in.
</div>

v-for

The v-for directive is used to render a list of items based on an array or an object. It iterates over each item and creates a copy of the element or component for each iteration.

Example:

<ul>

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

v-bind

The v-bind directive is used to dynamically bind an attribute or a prop to an expression or a data property. It allows you to dynamically update the value of an attribute or prop based on changes in your data.

Example:

<img v-bind:src="imageUrl">

v-on

The v-on directive is used to attach event listeners to elements. It allows you to listen to DOM events and execute methods or expressions when those events are triggered.

Example:

<button v-on:click="handleClick">

Click me
</button>

In addition to these built-in directives, Vue.js also allows you to create custom directives to extend the functionality of your application. Custom directives can be used to create reusable behaviors or implement complex interactions.

Directives are a powerful feature of Vue.js that enable you to manipulate the DOM and create dynamic behavior in your applications. Understanding how to use and create directives is essential to becoming proficient in Vue.js development.

Working with Directives

In Vue.js, directives are special attributes that can be added to HTML elements with the v- prefix. They allow you to add behavior to your HTML elements or manipulate the DOM based on certain conditions or events.

v-if and v-show

The v-if directive is used to conditionally render an element based on a given expression. The element will only be rendered if the expression evaluates to true. If the expression evaluates to false, the element is not rendered in the DOM.

The v-show directive, on the other hand, also conditionally renders an element based on a given expression. However, instead of completely removing the element from the DOM, it sets the element’s CSS display property to none, effectively hiding it from view. This allows the element to be quickly toggled on/off without the need to re-render it.

Here is an example of using v-if and v-show:

<div v-if="shouldRender">

This div is rendered using v-if.
</div>
<div v-show="shouldShow">
This div is rendered using v-show.
</div>

In the example above, the first div will only be rendered if the expression “shouldRender” evaluates to true. If it evaluates to false, the div will not be present in the DOM. On the other hand, the second div is always present in the DOM, but its display property is toggled between “block” and “none” based on the value of the expression “shouldShow”.

v-for

The v-for directive is used to render a list of items based on an array or an object. It creates a new instance of the element for each item in the array or object and sets the item as the data source for that instance. This allows you to easily render dynamic lists without the need to write repetitive code.

Here is an example of using v-for to render a list of items:

<ul>

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

In the example above, the v-for directive creates a new <li> element for each item in the “items” array. The <li> element’s content is dynamically bound to the value of the “name” property of each item. The :key attribute is used to provide a unique identifier for each rendered element, which helps Vue.js efficiently update the list when changes occur.

v-bind

The v-bind directive is used to bind an HTML attribute to a JavaScript expression or a Vue.js data property. It allows you to dynamically update the value of an attribute based on changes in your data.

Here is an example of using v-bind to bind the src attribute of an image element:

<img v-bind:src="imageUrl">

The example above binds the src attribute of the <img> element to the value of the “imageUrl” data property. Whenever the value of the “imageUrl” property changes, the src attribute of the image will be updated accordingly.

There are many other directives available in Vue.js that can help you manipulate the DOM or add behavior to your elements. These were just a few examples to get you started. Make sure to check out the official Vue.js documentation for more details about each directive and their usage.

FAQ:

What is reactivity in Vue.js?

Reactivity in Vue.js refers to the ability of the framework to automatically track changes in data and update the DOM accordingly. This allows for declarative rendering, where you only need to specify how the UI should look based on the data, and Vue.js takes care of updating it when the data changes.

How does reactivity work in Vue.js?

Under the hood, Vue.js uses a dependency tracking system. When you create a component, Vue.js scans the template and identifies any reactive data properties used in it. It then creates a dependency relationship between the component and those properties. When a property changes, Vue.js is able to identify the affected components and update only the necessary parts of the DOM.

Can I manually track changes in Vue.js?

Yes, you can manually track changes in Vue.js using watchers. Watchers allow you to watch for changes on specific properties and perform custom logic when they change. This can be useful for cases where you need more control over the update process, or need to perform async operations when a property changes.

What are computed properties in Vue.js?

Computed properties are properties that are calculated based on other reactive properties. They are defined as functions in the component’s computed option. Computed properties are cached and only re-evaluated when their dependent properties change. This makes computed properties a good choice for expensive or complex calculations.

What is the difference between computed properties and methods in Vue.js?

The main difference is that computed properties are cached based on their dependencies, while methods are called whenever the component re-renders. This means that computed properties are more efficient for calculations that don’t need to be re-evaluated every time, while methods are better suited for operations that need to be performed on demand.

Can I use reactivity in Vue.js without using the Vue instance?

No, reactivity in Vue.js relies on the Vue instance to track changes and update the DOM. If you want to leverage reactivity in your application, you’ll need to use the Vue instance to create components and manage your data.