How would you clone an object in JavaScript?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of JavaScript conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
There are four ways to clone an object in javascript. They are:
- Use the spread operator.
- Call the Object.assign() function.
- Use JSON parsing.
- Use the structuredClone() function.
const data = { name: "Alice", age: 26 }
// 1
const copy1 = { ...data }
// 2
const copy2 = Object.assign({}, data)
// 3
const copy3 = JSON.parse(JSON.stringify(data))
// 4
const copy4 = structuredClone(data)
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.