What are default props?
Assesses fundamental understanding of React conventions, runtime behavior, and memory/performance considerations.
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
The _defaultProps_ can be defined as a property on the component to set the default values for the props. These default props are used when props not supplied(i.e., undefined props), but not for null or 0 as props. That means, If you provide null value then it remains null value. It's the same behavior with 0 as well.
For example, let us create color default prop for the button component,
function MyButton {
// ...
}
MyButton.defaultProps = {
color: "red",
};
If props.color is not provided then it will set the default value to 'red'. i.e, Whenever you try to access the color prop it uses the default value
function MyButton() {
return <MyButton />; // props.color will contain red value
}
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.