locutus/esm/golang/time/AddDate.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

const toTimeDate = (value) => {
    const date = value instanceof Date ? new Date(value.getTime()) : new Date(value);
    if (Number.isNaN(date.getTime())) {
        throw new TypeError('AddDate(): invalid date input');
    }
    return date;
};
export function AddDate(value, years, months, days) {
    //      discuss at: https://locutus.io/golang/time/AddDate
    // parity verified: Go 1.23
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Adds years/months/days to a date using Go-like normalization behavior.
    //       example 1: AddDate('2011-11-18T15:56:35.000Z', 1, 2, 3).toISOString()
    //       returns 1: '2013-01-21T15:56:35.000Z'
    //       example 2: AddDate('2020-10-31T00:00:00.000Z', 0, 1, 0).toISOString()
    //       returns 2: '2020-12-01T00:00:00.000Z'
    //       example 3: AddDate('2024-02-29T00:00:00.000Z', 1, 0, 0).toISOString()
    //       returns 3: '2025-03-01T00:00:00.000Z'
    const date = toTimeDate(value);
    const year = date.getUTCFullYear() + Math.trunc(Number(years));
    const monthIndex = date.getUTCMonth() + Math.trunc(Number(months));
    const day = date.getUTCDate() + Math.trunc(Number(days));
    const hour = date.getUTCHours();
    const minute = date.getUTCMinutes();
    const second = date.getUTCSeconds();
    const millis = date.getUTCMilliseconds();
    return new Date(Date.UTC(year, monthIndex, day, hour, minute, second, millis));
}