Bytedance·Frontend Engineer·Technical Phone Screen·Intermediate

IntermediatePrefer not to say

Apr 2026Remote

Summary

Bytedance frontend round, just one coding question the whole time. The problem looked familiar but the trailing-call requirement tripped me up a bit.

Questions Asked (1)

Implement a throttle function that executes a callback once per time window, but if additional calls happen within that window, it remembers the most recent arguments and fires the callback with those arguments at the end of the window.

Algorithms & Data StructuresTechnical Trade-offs

Author's notes

I knew the basic throttle pattern but the 'remember latest args and re-execute at window end' part is where I fumbled.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the requirements: throttle with trailing edge execution using the latest arguments. Then outline a solution using a timer and a stored arguments variable, and walk through the logic step by step. Finally, discuss edge cases and potential improvements.

Pro tip: Mention that this is a 'throttle with trailing edge' and contrast it with debounce to show deep understanding. Also, highlight that you preserve the latest arguments and context (this) for the trailing call.

1. Clarify Requirements

Confirm that the function should execute immediately on the first call, then ignore subsequent calls until the window ends, but remember the latest arguments and execute again at the end if there were any calls during the window.

2. Design the Algorithm

Use a timer variable to track the throttle window. On each call, if no timer is active, execute immediately and start the timer. If a timer is active, store the latest arguments and context.

3. Implement the Timer Logic

When the timer expires, check if there are stored arguments. If so, execute the callback with those arguments and restart the timer; otherwise, clear the timer to allow immediate execution on the next call.

4. Handle Edge Cases

Consider leading/trailing options, cancellation, and context preservation. Discuss how to extend the basic implementation to support these.

5. Test and Validate

Walk through a few scenarios (e.g., rapid calls, spaced calls) to verify the behavior matches the requirements.

Key Points to Mention

Difference between throttle and debounce, and why this is a throttle with trailing edge.
Use of setTimeout and clearTimeout for timing control.
Storing the latest arguments and context (this) for the trailing call.
Ensuring the callback is not called more than once per window.
Potential memory leaks if not clearing timers properly.
Optional leading/trailing configuration and cancellation support.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.