When working with form inputs in React, you might encounter situations where an input field switches from being uncontrolled to controlled, or vice versa. This typically happens when the input's value is not managed consistently by the React component's state.
Solutions
Take Control:
Instead of allowing the browser to manage the text box, manage it through your React component’s state. This involves defining a state variable to store the input's value.
Update the Value:
Use an onChange event handler to update the state with the current value every time the user types in the text box. This ensures that the input field reflects the current state.
Display the Value:
Bind the input's value attribute to the state variable. This allows React to control the displayed value of the text box.
Using defaultValue for Uncontrolled Components:
If you want to use an uncontrolled component but still initialize it with a value, you can use the defaultValue prop. This way, React initializes the input field with the provided value, but it does not manage its subsequent changes.
Using Refs for Accessing Input Values:
If you need to access the input value without re-rendering the component, you can use refs. This approach is useful for scenarios where you need to retrieve the input value on form submission or another event without controlling the input's value through state.
look at the example illustrating both controlled and uncontrolled inputs using refs and defaultValue:
import React, { useState, useRef } from 'react';
function MyComponent() {
const [inputValue, setInputValue] = useState('');
const inputRef = useRef(null);
const handleChange = (event) => {
setInputValue(event.target.value);
};
const handleSubmit = (event) => {
event.preventDefault();
alert(`Submitted value: ${inputRef.current.value}`);
};
return (
<div>
<h2>Controlled Input</h2>
<input
type="text"
value={inputValue}
onChange={handleChange}
/>
<p>Write value: {inputValue}</p>
<h2>Uncontrolled Input with defaultValue</h2>
<input type="text" defaultValue="Initial Value" />
<h2>Input with Refs</h2>
<input type="text" ref={inputRef} placeholder="Type here..." />
<button onClick={handleSubmit}>Submit</button>
</div>
);
}
export default MyComponent;
This is the way to ensure that the input is always in sync with the component’s state, making it a controlled component and providing a better user experience.
