abschreibung

Deferred cost allocation utilities for inclusive date ranges.

Install

npm install abschreibung

Date Behavior

All date ranges are inclusive. A range from 2020-01-01 to 2020-01-01 has 1 day; a range from 2020-01-01 to 2020-01-02 has 2 days.

The package works with JavaScript Date values and normalizes calculations to calendar days.

Types

type DeferredCostAllocationMode = "monthly" | "yearly";

interface DeferredCostInput {
  startDate: Date;
  endDate: Date;
  totalCost: number;
}

interface DeferredCostPeriod {
  timeStart: string;
  timeEnd: string;
  days: number;
  costs: number;
}

DeferredCostPeriod.timeStart and DeferredCostPeriod.timeEnd are formatted as YYYY-MM-DD.

calculateDeferredCostAllocation

Calculates deferred cost periods by month or year. The default mode is yearly.

import { calculateDeferredCostAllocation } from "abschreibung";

const periods = calculateDeferredCostAllocation(
  {
    startDate: new Date("2020-01-01"),
    endDate: new Date("2020-02-01"),
    totalCost: 1000,
  },
  "monthly",
);

Returns:

[
  { timeStart: "2020-01-01", timeEnd: "2020-01-31", days: 31, costs: 968.75 },
  { timeStart: "2020-02-01", timeEnd: "2020-02-01", days: 1, costs: 31.25 },
];

calculateMonthlyDeferredCostAllocation

Calculates deferred cost periods split by calendar month.

import { calculateMonthlyDeferredCostAllocation } from "abschreibung";

const periods = calculateMonthlyDeferredCostAllocation({
  startDate: new Date("2020-01-31"),
  endDate: new Date("2020-02-02"),
  totalCost: 1000,
});

Returns:

[
  { timeStart: "2020-01-31", timeEnd: "2020-01-31", days: 1, costs: 333.3333333333333 },
  { timeStart: "2020-02-01", timeEnd: "2020-02-02", days: 2, costs: 666.6666666666666 },
];

If the full range is inside one calendar month, the function returns one period with the full totalCost.

calculateYearlyDeferredCostAllocation

Calculates deferred cost periods split by calendar year.

import { calculateYearlyDeferredCostAllocation } from "abschreibung";

const periods = calculateYearlyDeferredCostAllocation({
  startDate: new Date("2020-12-31"),
  endDate: new Date("2021-01-01"),
  totalCost: 1000,
});

Returns:

[
  { timeStart: "2020-12-31", timeEnd: "2020-12-31", days: 1, costs: 500 },
  { timeStart: "2021-01-01", timeEnd: "2021-01-01", days: 1, costs: 500 },
];

If the full range is inside one calendar year, the function returns one period with the full totalCost.

calculateDailyDeferredCost

Calculates the daily cost for an inclusive date range.

import { calculateDailyDeferredCost } from "abschreibung";

const costPerDay = calculateDailyDeferredCost({
  startDate: new Date("2020-01-01"),
  endDate: new Date("2020-01-03"),
  totalCost: 1000,
});

Returns:

333.3333333333333;

calculateInclusiveDayCount

Counts calendar days between two dates, including both the start and end date.

import { calculateInclusiveDayCount } from "abschreibung";

const days = calculateInclusiveDayCount(new Date("2020-02-01"), new Date("2020-03-01"));

Returns:

30;

Publishing

Pushing to the main branch publishes the package to npm through GitHub Actions.

Required repository secret:

• NPM_TOKEN: npm automation token with publish access for abschreibung.

The workflow checks whether the current package.json version already exists on npm. If it does, it bumps the patch version until it finds an unpublished version, commits the updated package.json and package-lock.json back to main, and publishes that version.