Creating a Dynamic Form in React
Creating a dynamic form involves working with application states and rendering.
1. Requirements
To follow along, you will need npm and Node.js installed on your computer.
2. Setting Up the Application
In your working directory create a new React application with the following command:
npx create-react-app gfg-dynamic-form
The above command will load a basic project template which will lay a foundation for our application. Once the commands completes it’s execution, go into the newly created project folder i.e. “gfg-dynamic-form“, and open the project in your favorite code editor, eg. VS code.
cd gfg-dynamic-form
3. Setting Up the Form Component
In the ./src folder of the application, create a new file called TodosForm.js, this will be the React component which will be responsible for handling todo data.
Javascript
import { useState } from "react"; function TodoForm() { const [todos, setTodos] = useState([{ name: "", label: "" }]); const handleTodoChange = (e, i) => { // Todo: Change todo at position i }; const handleAddTodo = () => { // Todo: Append a new empty todo }; const handleDeleteTodo = (i) => { // Todo: Delete todo at position i }; const handleSubmit = (event) => { event.preventDefault(); console.log(todos); setTodos([]); }; return ( <form onSubmit={handleSubmit}> {todos.map((todo, index) => ( <div key={index}> <input type="text" placeholder="Name" name="name" value={todo.name} onChange={(e) => handleTodoChange(e, index)} required /> <select value={todo.label} name="label" onChange={(e) => handleTodoChange(e, index)} required > <option value="">label</option> <option value="important">Important</option> <option value="not-important">Not Important</option> </select> <button onClick={() => handleDeleteTodo(index)}>Delete</button> </div> ))} <button onClick={handleAddTodo}>Add Todo</button> <button type="submit">Submit Todos</button> </form> ); } export default TodoForm; |
In the above implementation, the code provided creates a user interface that allows users to add their todo item using a form. It utilizes React’s useState hook to store an array of todo objects with their respective name and corresponding label. To update todo data, the input fields trigger the handleTodoChange() function, passing an index parameter to specify which todo’s information needs updating. If a new todo should be added, handleAddTodo() would be responsible for adding an empty entry for the new todo. In the same way, handleDeleteTodo() will be responsible for removing a todo record based on the given index. Once the form is submitted, handleSubmit() executes additional operations, in this case we will try to make it simple by just logging the data to the console window. The JSX code generates input fields for each todo and includes buttons to add or delete todos and submit their data.
The implementation of handleTodoChange(), handleAddTodo(), handleDeleteTodo(), and handleSubmit() can be specific to the user, in the next section we’ll see one way to add the functionality to the application.
4. Setting up Dynamic Functionality
Now in the same file, create functions for implementing the Addition, Deletion, and Modification of todos.
Javascript
import { useState } from "react"; function TodoForm() { const [todos, setTodos] = useState([{ name: "", label: "" }]); const handleTodoChange = (e, i) => { const field = e.target.name; const newTodos = [...todos]; newTodos[i][field] = e.target.value; setTodos(newTodos); }; const handleAddTodo = () => { setTodos([...todos, { name: "", label: "" }]); }; const handleDeleteTodo = (i) => { const newTodos = [...todos]; newTodos.splice(i, 1); setTodos(newTodos); }; const handleSubmit = (event) => { event.preventDefault(); console.log(todos); setTodos([]); }; return ( ... ); } export default TodoForm; |
The above section defines different functionalities, let’s see each one of them one by one,
A. handleTodoChange()
This function is triggered whenever a user makes changes to any of the input fields. It takes two parameters: the event object ‘e‘, which provides information about the change event, and the index ‘i’ of the todo that needs to be updated. The function first retrieves the field name from the event object’s name attribute. Then, it creates a copy of the todo’s array using the spread operator. This copy ensures that we do not directly modify the original array. Next, it updates the specific property of the individual todo with the new value obtained from the event object. Finally, it applies these changes by setting state with setTodos() which allows for appropriate updates to be reflected in our application.
B. handleAddTodo()
This function is triggered whenever a user clicks on the ‘Add Todo’. It does not take any parameter. The function creates a new object with empty name and label property. Then, the spread operator is used to create a new array with the new empty object appended to it. Finally, it applies these changes by setting state with setTodos() which allows for appropriate updates to be reflected in our application.
C. handleDeleteTodo()
This function is triggered when the user clicks on the ‘Delete’ button. It takes only one parameters: the index ‘i’ of the todo that needs to be deleted. Then, it creates a copy of the todo’s array using the spread operator. This copy ensures that we do not directly modify the original array. The splice() method is then used to delete the todo at the specified index. Finally, it applies these changes by setting state with setTodos() which allows for appropriate updates to be reflected in our application.
D. handleSubmit()
This function is triggered when the form is submitted when the user hits the ‘Submit Todos’ button. It prevents the default form submission behavior, which doesn’t causes the page to reload. The console displays the current todo’s array and shows the entered todo’s list. After submission, the form is cleared by setting the todo’s state to an empty array.
5. Integrating the Component
Once you have the component ready, add it to the App.js file.
Javascript
import React from 'react'; import './App.css'; import TodosForm from './TodosForm'; function App() { return ( <div className="App"> <h1>Dynamic Todo List</h1> <TodosForm /> </div> ); } export default App; |
6. Dynamic Form is Ready Now!
You should see the form rendered in the image below.
Todo List UI
You should see the below output logged into the console, once you hit the submit button
output
Congratulations! You now have a fully functional dynamic form at your disposal. This form showcases the power of React’s component-based structure and state management, ensuring a seamless and engaging user experience.
How to Build Dynamic Forms in React?
React, a popular library built on top of javascript was developed by Facebook in the year 2013. Over the coming years, React gained immense popularity to emerge as one of the best tools for developing front-end applications. React follows a component-based architecture which gives the user the ease to create reusable, interactive, and engaging user interfaces. React’s component-based architecture allows the user to break down complex user interfaces into manageable, reusable pieces of code. Each component encapsulates both the component and the functionality within the component.
In ReactJS, the flexibility it possesses is not only restricted to generating static interfaces but also extends to the designing of dynamic interfaces. Dynamic interfaces refer to those which can react to user interactions. Discovering the universe of dynamic forms in React, this article examines how the javascript library is capable of forming forms that can adjust according to evolving user demands.
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