Custom React JS Hooks: What Are They and When to Use Them?

What is a custom hook? How do I make a custom hook in React JS? When would you use React custom Hooks? Want to know everything about custom React JS hooks? Keep on reading.

What is a custom hook? How to make a custom hook in React JS? 

Custom React JS hooks are reusable functions that a React JS software developer can use to add special and unique functionality to the React applications. Usually, if there is a requirement to add a feature, one can install a third-party library and solve the problem. But what if there is no such library with hooks that can be used? This problem is solved by using custom React JS hooks.

A custom hook is a special JavaScript function whose name starts with ‘use’ and can be used to call other hooks. Let’s take a look at some major differences between a custom React JS hook and React JS components:

• A custom hook does not require a specific signature.
• A software developer can choose what argument the custom hook has and what should the argument return.
• A custom hook always starts with the name ‘use’.

Here’s an example of how using a Custom React JS hook can help you write clean code and reduce the rendering time:

What are the advantages of using a custom React JS hook?

Custom React JS hooks offer three major benefits over standard library hooks: Reusability, readability, and testability.

1. Reusability

   Custom React JS hooks offer reusability as when a custom hook is created, it can be reused easily, which makes the code cleaner and reduces the time to write the code. It also enhances the rendering speed of the code as a custom hook does not need to be rendered again and again while rendering the whole code.
   

2. Readability

   Instead of using High-Order Components (HOCs), one can use custom hooks to improve the readability of the code. Complex codes can become hard to read if layers of providers surround the components, consumers, HOCs, render props, and other abstractions, generally known as wrapper hell.
   
   

   Custom React JS Hooks provide better readability | Source: confluent.io

   
   On the other hand, using custom React JS hooks can provide a cleaner logic and a better way to understand the relationship between data and the component.
   

3. Testability

   Generally, the test containers and the presentational components are tested separately in React. This is not a trouble when it comes to unit tests. But, if a container contains several HOCs, it becomes difficult as you will have to test the containers and the components together to do the integration tests.
   
   Using custom React JS hooks, this problem can be eliminated as the hooks allow you to combine containers and components into one component. It also makes it easier to write separate unit tests for custom hooks. Using custom hooks also makes it easier to mock hooks when compared to mock HOCs as it is similar to mocking a function.

Summary

Custom React JS hooks can help developers save time, are reliable, reusable, and make the code clean. Creating custom React JS hooks is relatively easy, and you can search for many open sources where you can get some custom hooks from the library already created by developers.

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FAQs

1. How do you make a custom hook in React?
   
   A custom React JS hook is created by using the ‘use’ prefix. For eg, a custom hook can be named ‘useLocalStorage’ or ‘useBoolean’. A custom hook will consist of one or more React JS hooks from the library. For more information on how to create a Custom hook, take a look at this video:
   
   
2. When would you use React custom Hooks?
   
   If you have one or multiple React hooks that will be used at multiple locations in a code, you should use custom React JS hooks. This helps in making the code more readable and make the code clean.