Conditional Rendering in Vue 3: A Comprehensive Guide

In Vue 3, conditional rendering allows you to control the rendering of DOM elements based on certain conditions. This is useful for building dynamic and interactive user interfaces that can change based on user input or application state. In this tutorial, we'll take a look at how to use conditional rendering in Vue 3 to build responsive and interactive UIs.

To render an element conditionally in Vue 3, you can use the v-if directive. This directive takes a boolean expression as an argument, and renders the element it is applied to if the expression is true. If the expression is false, the element is not rendered.

For example, let's say you have a data property called isLoggedIn that you want to use to control the rendering of a login form. You can do this using the v-if directive:

<template>
  <form v-if="!isLoggedIn">
    <!-- login form elements -->
  </form>
</template>

<script>
export default {
  data() {
    return {
      isLoggedIn: false,
    };
  },
};
</script>

In this example, the v-if directive is applied to the form element, and the expression !isLoggedIn is used as the argument. This expression evaluates to true if the isLoggedIn property is false, and false if it is true. As a result, the form is only rendered if the user is not logged in.

You can use the v-if directive to conditionally render any DOM element, including elements, components, and even entire templates. For example, you can use it to render a loading spinner while data is being fetched:

<template>
  <div v-if="isLoading">
    <!-- loading spinner elements -->
  </div>
  <div v-else>
    <!-- data elements -->
  </div>
</template>

<script>
export default {
  data() {
    return {
      isLoading: true,
    };
  },
};
</script>

In this example, the v-if directive is used to render a loading spinner while the isLoading property is true, and the v-else directive is used to render data elements when the isLoading property is false. This allows you to create a dynamic and interactive UI that can adapt to changing data states.

By using conditional rendering in combination with other Vue 3 features, such as data binding and computed properties, you can create responsive and interactive UIs that change based on user input and application state. Whether you're building a simple form or a complex single-page application, conditional rendering is a key tool for building dynamic and interactive user interfaces with Vue 3.