Unix timestamp units: seconds, milliseconds, microseconds and nanoseconds

The same integer can name instants decades apart when interpreted in seconds or milliseconds. EpochLens makes the unit a required part of the input contract.

Seconds are the classic Unix unit

Unix time counts elapsed SI-like seconds from 1970-01-01T00:00:00Z under POSIX conventions. APIs often serialize that count as an integer, but their contract still needs to say seconds.

Sub-second units preserve different evidence

Milliseconds divide one second by 1,000, microseconds by one million and nanoseconds by one billion. Converting through a floating-point Number can lose large exact integers, so EpochLens uses BigInt.

Precision and date range are separate

An exact nanosecond integer can describe an instant outside JavaScript Date's representable calendar range. EpochLens rejects that result instead of wrapping or clipping it.