Common Vue.js Development Mistakes and How to Avoid Them: Part 2 ✅
Tags: webdev, vue, javascript, programming
Published: 2023-10-18 18:33:55

Do you ever find yourself in a situation where you're passing a prop to a component, and then passing that same prop to a child component, and then to a grandchild component? If so, you've encountered a common challenge in Vue.js development known as "**prop drilling.**" 

![prop drilling demo](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/2p1eimou4wjmh6trueyu.jpeg)

But what exactly is prop drilling, and why is it considered an anti-pattern in Vue.js? The same issue can also arise with event emitting, creating what's known as "event tunneling." Both of these techniques, prop drilling and event tunneling, can make your code less intuitive and harder to maintain.

**Prop Drilling in Vue.js:**

Prop drilling occurs when you pass a prop through multiple levels of nested components to reach its final destination. While Vue's component-based architecture encourages reusability and modularity, this practice can lead to complexities that make your codebase less elegant and maintainable.

**Event Tunneling in Vue.js:**

On the other hand, event tunneling happens when you emit an event from a deeply nested child component and then capture and handle that event at a higher-level parent component. This can also result in code that's challenging to follow, as it breaks the clear data flow that Vue.js promotes.

So, how can we avoid these anti-patterns and make our Vue.js code more efficient and easier to maintain?

---

**Solution 1: Use `provide` and `inject` in Vue.js**


![Provide/Inject demo](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/ujcy8z1zb82siy6hbmqm.jpeg)

One effective method to combat prop drilling and event tunneling in Vue.js is by leveraging the built-in feature called `provide` and `inject`. This powerful duo allows you to provide data at a higher component level and then inject that data deep down the component tree, regardless of how many nested levels you have. Read the docs [here](https://vuejs.org/guide/components/provide-inject.html#prop-drilling)

A noteworthy example of this pattern in action is `Vue Router`. It provides the router and route objects throughout your application by offering them at the App component level and injecting them into each individual component. This approach eliminates the need to accept route or router props in every single component, leading to a cleaner and more maintainable codebase.


![Example of provide/inject being used in the vue-router docs](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/jz07t7x3roki3ifavk0y.jpeg)

By embracing `provide` and `inject`, you can ensure that data flows seamlessly through your Vue.js application, reducing the need for excessive prop passing and event emitting. This not only enhances code readability but also simplifies the maintenance of your components, making your development journey smoother and more efficient.

The syntax for using `provide` and `inject` in Vue.js is quite straightforward. In the parent component, you call the `provide` function with two parameters: an identifier (known as the injection key) and the data you want to pass down. Here's a snippet of code illustrating this:

```vue
<script setup>
import { ref, provide } from "vue";
import Child from "./Child.vue";

const todos = ref(["Get Lunch", "Play Ball", "Check Todo", "Call John"]);
provide("todoList", todos);
</script>
<template>
  <Child />
</template>
```

In this example, we're providing a list of todos with the identifier "todoList" using the `provide` function. This data can now be injected into the `Child` component, making it accessible there without the need for prop chaining or event emission. This method simplifies the data flow and improves the maintainability of your Vue.js application. Every direct or indirect descendant of this component will have access to this data using the `inject` function like so:

```vue
<script setup>
import { shuffle } from "lodash";
import { inject } from "vue";

const todos = inject("todoList");
const shuffleItems = () => {
  todos.value = shuffle(todos.value);
};
</script>
<template>
  <ul>
    <li v-for="todo in todos" :key="JSON.stringify(todo)">{{ todo }}</li>
  </ul>
  <button @click="shuffleItems">Shuffle Items</button>
</template>
```
I really believe this is an under-utilized feature in Vue.js and I don't see it often.
You can check out and play around with this concept in [this sandbox environment](https://codesandbox.io/s/musing-swirles-gvsr7j?file=/src/components/Parent.vue)


**Solution 2: Use a global state management option**

Using Vue's global state management tools is another powerful solution to address the challenges of prop drilling and event tunneling in your Vue.js applications. Instead of maintaining state at a higher-level component and passing it down, global state management enables you to store and manage the state outside of the components themselves. This makes the state accessible in any component within your application, enhancing flexibility and maintainability.

There are several options available for global state management in Vue.js, including:

1. **Composables:** Vue 3 introduced Composition API, which includes the use of composable functions to manage and share state across components.

2. **Vuex:** Vuex is a popular state management library for Vue.js, designed specifically for managing application-level state and actions.

3. **Pinia:** Pinia is a state management solution recommended by the Vue.js core team. It offers a robust and highly efficient way to manage state in Vue applications.

While I won't delve into the specific details of each option here, I encourage you to explore the documentation for these tools to choose the one that best suits your project's needs. Global state management is a powerful strategy that not only mitigates prop drilling and event tunneling but also empowers you to build scalable and maintainable Vue.js applications. 

For a more in-depth understanding of each tool, consider referring to their respective documentation ([vuex](https://vuex.vuejs.org/guide/), [pinia](https://pinia.vuejs.org/), [composables](https://vuejs.org/guide/reusability/composables.html)).

That wraps up this article on common Vue.js pitfalls! Stay tuned for the next part, where we'll delve into yet another common mistake in Vue.js development. See you in the next article, and happy coding! 💻🥳