A Dispute Window from a Contract

A Dispute Window from a Contract

A service contract gives 14 days to dispute an invoice. Hard-coding 30, the window most contracts use, misses the deadline by two weeks.

The naive approach

// The naive approach: a dispute window copied from somewhere else
const DISPUTE_DAYS = 30;
const invoiced = new Date("2026-03-05T00:00:00Z");
new Date(invoiced.getTime() + DISPUTE_DAYS * 86400e3).toISOString().slice(0, 10); // "2026-04-04"
// This contract gives 14 days: the dispute deadline is 2026-03-19

Watch it break

The naive approach silently produces wrong results — there is no GMT equivalent to demonstrate because the failure is not using GMT.

Why

The windows are the contract's. GMT carries no number, so the caller passes 14, 14 and 45.

The gmt approach

import { billingTimeline } from "@northguild/gmt/intermodal";

const contract = { issueDays: 14, disputeDays: 14, resolutionDays: 45 };

// A request received on or before the 14-day dispute deadline.
billingTimeline({ anchorOn: "2026-03-01", invoiceIssuedOn: "2026-03-05", requestReceivedOn: "2026-03-18" }, contract);
// { invoiceDeadline: "2026-03-15", issuedByDeadline: true, disputeDeadline: "2026-03-19",
//   requestedByDeadline: true, resolutionDeadline: "2026-05-02" }

// The same contract, a request received two days later: after the dispute deadline.
billingTimeline({ anchorOn: "2026-03-01", invoiceIssuedOn: "2026-03-05", requestReceivedOn: "2026-03-20" }, contract);
// { invoiceDeadline: "2026-03-15", issuedByDeadline: true, disputeDeadline: "2026-03-19",
//   requestedByDeadline: false, resolutionDeadline: "2026-05-04" }

Same widget, working

dateswindows

output

 

Change the dispute window to 30 in the Billing Deadlines widget and watch every later date move. The full rules are in Intermodal: Billing Deadlines.