LWCBeginnerapitrackreactivity
What is the difference between @api and @track?
Real World Scenario
A parent passes a record Id to a child component. You explain public properties and reactivity.
Expected Answer
• @api marks public properties the parent can set from markup or other components
• Primitive @api properties are reactive by default in modern LWC
• @track was needed for deep reactivity on object properties; plain fields are reactive now for most cases
• Use @api for inputs from parent; internal state uses class fields
• Clear naming helps parent-child contracts stay maintainable
Follow-Up Questions & Answers
Click to expand — each follow-up includes a direct, interview-ready answer
Rarely on modern API versions for deep object mutation edge cases. Prefer spreading objects to trigger re-render when unsure.
Architect Perspective
If asked @track, show you know it is mostly legacy—signals current LWC knowledge.