halfEven

Divide and round towards the nearest neighbor, rounding to the nearest even integer when exactly halfway.

This rounding mode is also known as bankers rounding. It rounds to the nearest integer, and when the value is exactly halfway between two integers, it picks the even one. This reduces cumulative rounding bias in financial calculations.

For example, 1.5 rounds to 2, 2.5 rounds to 2, 3.5 rounds to 4, and -2.5 rounds to -2.

Usage

Pass this function as the last argument to multiply, allocate, or transformScale to control how remainders are handled.

Code examples

Use with multiply

import { dinero, multiply, halfEven } from 'dinero.js';
import { USD } from 'dinero.js/currencies';

const d = dinero({ amount: 305, currency: USD });

multiply(d, { amount: 21, scale: 1 }, halfEven); // a Dinero object with amount 6405 and scale 3

Use with transformScale

import { dinero, transformScale, halfEven } from 'dinero.js';
import { USD } from 'dinero.js/currencies';

const d = dinero({ amount: 1050, currency: USD, scale: 3 });

transformScale(d, 2, halfEven); // a Dinero object with amount 104 and scale 2