Format relative timestamps

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Format relative timestamps · UIHero

Format relative timestamps

Convert dates around an injected clock into stable, threshold-aware past and future labels.

EasyJavaScript Dates

30 min0% acceptance

Description

Implement formatRelativeTimestamp without reading the ambient clock. It returns just now near zero, chooses second, minute, hour, day, month, or year units at documented boundaries, supports future values, and rejects invalid dates.

Requirements

The solution exports the required formatRelativeTimestamp API from the editable module.
Just now works deterministically for the documented normal, boundary, and repeated-use scenarios.
Past thresholds works deterministically for the documented normal, boundary, and repeated-use scenarios.
Future thresholds works deterministically for the documented normal, boundary, and repeated-use scenarios.
Boundary values works deterministically for the documented normal, boundary, and repeated-use scenarios.
Injected now works deterministically for the documented normal, boundary, and repeated-use scenarios.
Invalid date works deterministically for the documented normal, boundary, and repeated-use scenarios.

Five minutes ago

Input

value 11:55 UTC and injected now 12:00 UTC

Expected output

5 minutes ago

Explanation

The injected clock makes the result independent of runtime time and timezone.

Constraints

Require the now argument rather than calling Date.now
Use deterministic English labels
Throw RangeError for invalid date values

Hints

Hint 1

Convert both inputs to epoch milliseconds before selecting a unit.

Hint 2

Choose thresholds from smallest to largest and keep sign separate from magnitude.

Hint 3

Test values exactly on both sides of each unit boundary.

JavaScriptdatesformatting

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