What is a decorator?
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
A decorator is an expression that evaluates to a function and that takes the target, name, and decorator descriptor as arguments. Also, it optionally returns a decorator descriptor to install on the target object. Let's define admin decorator for user class at design time,
function admin(isAdmin) {
return function(target) {
target.isAdmin = isAdmin;
}
}
@admin(true)
class User() {
}
console.log(User.isAdmin); //true
@admin(false)
class User() {
}
console.log(User.isAdmin); //false
Candidate Response Strategy & Interview Tips
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- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
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