The Timezone Trap

Users near midnight UTC receive a daily report for the wrong calendar range, while the same request looks correct in other time zones.

Initial failing signalReport day starts at local midnight instead of UTCExpected behavior: The report starts at the UTC day boundary, 2026-05-31T00:00:00.000Z. · actual behavior: The report starts at a timezone-shifted local boundary instead.

Progress

1Reproduce the bugRun checks

2Edit the fixOpen

3Pass checksOpen

4Submit fixOpen

Reproduction Steps

Run npm test.
Run the report-range checks under more than one time zone.
Trace how the requested day becomes start and end timestamps.
Make the calendar semantics explicit without changing the requested day.

Focus Mode

Start

src/report-range.js

Likely area

src/report-range.js

Challenge Coach

Hints reveal broad direction first, then narrow toward the suspect path without showing hidden tests or exact solution code.

TopicDate/Time

DifficultyMedium

Est. time23 min

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Evidence Map

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workspace

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