Countdown / Days-Until Timer implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t5-018

Effect

Computation or source lookup only

Input and validation requirements

The timezone-less target produces different valid countdowns under plausible conventions: 24 hours when interpreted as UTC versus 28 hours when interpreted as America/New_York. The instrument should require or explicitly document timezone handling.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "target_datetime": "2025-03-10T12:45:00+00:00",
    "now": "2025-03-08T10:15:00+00:00"
  },
  "expected_outputs": {
    "delta_seconds": 181800,
    "remaining_days": 2,
    "remaining_hours": 2,
    "remaining_minutes": 30,
    "remaining_seconds": 0
  },
  "working": "delta = target − now = 2025-03-10 12:45 − 2025-03-08 10:15. From March 8 10:15 to March 10 10:15 = 2 days = 2 × 86400 = 172800 seconds. From 10:15 to 12:45 = 2 hours 30 minutes = (2 × 3600) + (30 × 60) = 7200 + 1800 = 9000 seconds. Total delta = 172800 + 9000 = 181800 seconds = 2 days, 2 hours, 30 minutes, 0 seconds."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json