Grokking Node.js Design Patterns for Interviews/

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Solution: Measure Execution Time for an Async Task

Solution: Measure Execution Time for an Async Task

Wrap an asynchronous function with a decorator that measures and logs execution time transparently.

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Solution explanation

  • Lines 2–6: We define fetchUser, a mock async service that resolves after 100 ms. It simulates an I/O call such as fetching from a database or API.

  • Lines 9–17: We build withTiming(fn), a decorator that:

    • Captures the start time with Date.now() before calling the original function. ...