Written by Phuong Nguyen – Software Engineer, Atlantic Team
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Custom Hook is a popular subject in ReactJS and React Native development. Previously, developers based on classes to create components, but since React 16.8, hooks have gained popularity as a simpler alternative. Hooks enable us to encapsulate lifecycle functionality within the component, eliminating the need for separate functions required by classes.

In ReactJS and React Native, components are primarily responsible for displaying UI elements. However, there are situations where we need a component to provide logical data while still utilizing lifecycle management and hooks which is where custom hooks come in. So, it’s time to bid farewell to the old ways and embark on a new journey with hooks. The era of hooks has come. 

Let’s explore the significance of Custom Hooks and learn how to implement them today.

What is Custom Hook?

In React, a custom hook is a unique JavaScript function that begins with ‘use’ and is capable of invoking other hooks. These custom hooks serve as reusable functions that extract and reuse stateful logic across multiple components. They offer a convenient way to encapsulate complex functionality within a single function, streamlining the sharing and reusability of that logic throughout your application.

Why should we use custom hooks?

– Reusability: Custom hooks promote code reusability by enabling you to encapsulate and share stateful logic across various components. Instead of duplicating code or implementing the same logic repeatedly, you can extract it into a custom hook and reuse it when needed. It saves more time, reduces code duplication, and enhances overall productivity.

– Code Organization: Custom hooks contribute to improved code organization and readability. Abstracting complex logic into custom hooks makes your component code becomes more focused and concise. This separation of concerns makes it easier to understand the purpose and behavior of each component, leading to better code maintainability.

– Modular Architecture: Custom hooks enable a more modular code architecture. They allow you to separate the underlying logic from the UI-related code in your components. This separation of concerns makes your components more lightweight, and easier to simplify collaboration between developers working on different aspects of the application.

– Abstraction of Complexity: Custom hooks can abstract away complex logic, making it easier to work with. By encapsulating intricate state management, side effects, or other functionality within a custom hook, you can provide a simple and intuitive interface for using that logic. This abstraction helps to reduce the cognitive load when working with complex features.

– Testing: Custom hooks can improve the testability of your code. Since hooks are just functions, you can easily test them in isolation without the need for rendering components. This facilitates more comprehensive unit testing and simplifies mocking dependencies or simulating specific scenarios.

– Community and Code Sharing: By utilizing custom hooks, you can tap into a vast community of developers who create and share hooks. Many open-source libraries and frameworks provide custom hooks that encapsulate specific functionalities or solve common problems. Leveraging these hooks can accelerate your development process and benefit from the collective knowledge of the community.

How to Create a Custom Hook?

Step 1: Identify the Logic to be Abstracted

Step 2: Import Dependencies

Inside your custom hook file, import any necessary dependencies or hooks from the React library that you’ll need for your custom hook logic. For example, you may need to import useState, useEffect, or other hooks based on your requirements.

Step 3: Define the Custom Hook Function

Create a function that defines your custom hook. It should be named starting with “use” to adhere to the rules of hooks. This function will encapsulate the logic you want to reuse.

Step 4: Implement the Custom Hook Logic

Inside the custom hook function, implement the desired logic or functionality. It could involve setting up a state, managing side effects, accessing context, or any other relevant operations.

Step 5: Return Values

Determine what values or functions should be returned from the custom hook. These will be the shared resources that can be utilized by components using the hook.

Step 6: Export the Custom Hook

At the end of the custom hook file, export the custom hook function so that it can be imported and used in other components.

Step 7: Use the Custom Hook in Components

Import and use the custom hook in your React components by invoking it and destructure any returned values or functions

The content above tells us some information about custom hooks and how to create them. So, our readers, please keep reading, the second part of this blog will show you specific examples of hooks and help you clearly know how hooks work in ReactJS and React Native.