What is callback in callback?
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
You can nest one callback inside in another callback to execute the actions sequentially one by one. This is known as callbacks in callbacks. Beware, too many levels of nesting lead to Callback hell
loadScript("/script1.js", function (script) {
console.log("first script is loaded");
loadScript("/script2.js", function (script) {
console.log("second script is loaded");
loadScript("/script3.js", function (script) {
console.log("third script is loaded");
// after all scripts are loaded
});
});
});
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.