Title: How to Fix the Type ‘MutableRefObject’ Error in React
Introduction
If you are working with React and encounter the error message “Type ‘MutableRefObject’ is not assignable to type ‘LegacyRef’ or ‘RefObject’,” you’re in the right place. This error can be frustrating, but don’t worry – in this article, we will explain the issue and provide a step-by-step solution.
The Error Explained
The error message you are seeing suggests that there is a type mismatch related to the useRef hook in React. It indicates that the hook expects either an HTML element or null, but you might be passing in undefined, resulting in this error.
Solution
To fix this error, make the following changes to your code:
Step 1: Pass null as an Initial Value
When using the useRef hook, pass null as the initial value. This tells React that the ref can either hold a reference to an HTML element or be null.
const handleRef = React.useRef<HTMLInputElement | null>(null);
Step 2: Update the Ref Type
You need to update the type of the ref to match the new initialization. Change the type from LegacyRef to RefObject.
const handleRef = React.useRef<HTMLInputElement | null>(null);
Step 3: Handle the Current Value Properly
Ensure that you handle the current value of the ref correctly in your code. Check if the current value is defined before accessing any properties or methods of the HTML element.
if (handleRef.current) {
handleRef.current.checked = checked;
}
Revised Code
Here’s the updated code with the necessary changes:
const InputElement = React.forwardRef((props: any, ref) => {
const handleRef = React.useRef<HTMLInputElement | null>(null);
React.useImperativeHandle(ref, () => ({
setChecked(checked: boolean) {
if (handleRef.current) {
handleRef.current.checked = checked;
}
}
}), []);
return (
<input ref={handleRef} type="checkbox" />
);
});
Conclusion
By following these steps, you should be able to fix the “Type ‘MutableRefObject’ is not assignable to type ‘LegacyRef’ or ‘RefObject'” error in React. Make sure to pass null as the initial value, update the ref type, and handle the current value properly in your code. With these adjustments, your code should work as expected without any type errors.
We hope this article has been helpful to you. If you have any further questions, feel free to leave a comment below!