# Mastering Form Management with React useForm Plugin Library
Introduction:
Managing forms in web applications can be a complex task, especially when dealing with validation rules, error handling, and form submissions. The React `useForm` plugin library offers a powerful and elegant solution to simplify form management in React applications. In this tutorial, we will walk through a comprehensive example of using the `useForm` library to handle form lifecycle events, such as validations, rules, and form submissions. By the end of this tutorial, you will have a solid understanding of how to use the React `useForm` plugin library to efficiently manage forms in your React applications.
Prerequisites:
* Basic understanding of JavaScript and React
* Familiarity with React functional components and hooks
* Knowledge of form validation and handling in web applications
Getting Started:
To begin, let's install the React `useForm` plugin library by running the following command:
```javascript
npm install react-hook-form
```
Now that we have the library installed, let's dive into a practical example of using the `useForm` library to manage a form lifecycle.
Example: Create and Update Client Action Items
In this example, we will create a form to create and update client action items. The form will include fields for `title`, `category`, `description`, and `target_date`. We will use the `useForm` library to manage form state, handle validations, and submit the form data to an API.
Full Code Example;
```javascript
import { useForm } from 'react-hook-form';
export default function CreateClientActionItem({item}) {
const {
register,
handleSubmit,
formState: {
errors
}
} = useForm({
defaultValues: {
title: item?.title ?? '',
category: item?.category ?? '',
description: item?.description ?? '',
target_date: item?.target_date ?? '',
}
});
const onSubmit = (data) => {
let url = '/test/store-url';
axios.post(url, data).then((res) => {
if (res.data.status === 'success') {
alert("Success");
} else {
alert("Error");
}
}).catch((err) => {
notifyError("Unknown error occurred while creating action item")
});
}
const onUpdate = (data) => {
let url = '/test/update-url';
axios.put(url, data).then((res) => {
if (res.data.status === 'success') {
alert("Success");
} else {
alert("Error");
}
}).catch((err) => {
notifyError("Unknown error occurred while updating action item")
});
}
const onError = (data) => {
console.log(data);
}
return
}
```
Code Explanation:
**1\. Import** `useForm`**:**
Start by importing the `useForm` hook from the library:
```javascript
import { useForm } from 'react-hook-form';
```
**2\. Initialize** `useForm`**:**
In the `CreateClientActionItem` functional component, initialize the `useForm` hook and destructure its returned properties:
```javascript
const {
register,
handleSubmit,
formState: {
errors
}
} = useForm({
defaultValues: {
title: item?.title ?? '',
category: item?.category ?? '',
description: item?.description ?? '',
target_date: item?.target_date ?? '',
}
});
```
The `defaultValues` option allows you to set initial values for the form fields.
In this example, we use the optional chaining operator “`?”` and the nullish coalescing operator “`??”` to set the default values to empty strings if `item` is not provided.
**3\. Register form fields:**
To register form fields with the `useForm` hook, use the `register` function provided by the hook. The `register` function takes two arguments: the field name and an optional configuration object. The configuration object can include validation rules, such as `required`, `minLength`, and `maxLength`. If a validation rule fails, an error message is provided and stored in the `errors` object.
For example, registering the `title` field with validation rules:
```javascript
```
Similarly, register the `category`, `description`, and `target_date` fields with appropriate validation rules.
**4\. Handle form submission:**
The `handleSubmit` function is used to manage form submissions. It takes two arguments: a function to be executed on a successful submission and a function to be executed if there are any errors.
In our example, we use the `onSubmit` function for creating a new action item and the `onUpdate` function for updating an existing one:
```javascript