sainsburys-date/dist/index.js

Basic functions to convert a Date object into Sainsbury's financial calendar components

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const EPOCH_YEAR = 1970;
const EPOCH_DAY_OFFSET = 129; // Days between 1970-01-01 (Date(0)) and the theoretical 1970 P1 W1
const MILLIS_IN_DAY = 24 * 60 * 60 * 1000;
const QUARTERS_IN_YEAR = 4;
const PERIODS_IN_YEAR = 13;
const DAYS_IN_PERIOD = 28;
const DAYS_IN_YEAR = PERIODS_IN_YEAR * DAYS_IN_PERIOD;
const DAYS_IN_WEEK = 7;
const PERIODS_UP_TO_QUARTER = [0, 3, 6, 10];
function fromDate(date) {
    if (!date) {
        return undefined;
    }
    const daysBetween = new Date(date).getTime() / MILLIS_IN_DAY - EPOCH_DAY_OFFSET;
    const days = Math.ceil(daysBetween) % DAYS_IN_YEAR; // Number of days into the financial year
    const period = Math.floor(days / DAYS_IN_PERIOD) + 1;
    let quarter;
    switch (period) {
        case 1:
        case 2:
        case 3:
            quarter = 1;
            break;
        case 4:
        case 5:
        case 6:
            quarter = 2;
            break;
        case 7:
        case 8:
        case 9:
        case 10:
            quarter = 3;
            break;
        case 11:
        case 12:
        case 13:
            quarter = 4;
            break;
        default:
    }
    return {
        year: Math.floor(daysBetween / DAYS_IN_YEAR) + EPOCH_YEAR,
        quarter,
        period,
        week: Math.floor((days % DAYS_IN_PERIOD) / DAYS_IN_WEEK) + 1,
    };
}
function toDate(options) {
    let days = EPOCH_DAY_OFFSET;
    if (options.year) {
        const yearOpt = options.year;
        days += (yearOpt - EPOCH_YEAR) * DAYS_IN_YEAR;
    }
    if (options.quarter) {
        const quarterOpt = options.quarter - 1;
        days += Math.floor(quarterOpt / QUARTERS_IN_YEAR) * DAYS_IN_YEAR;
        days += (PERIODS_UP_TO_QUARTER[quarterOpt % QUARTERS_IN_YEAR] || 0) * DAYS_IN_PERIOD;
    }
    if (options.period) {
        const periodOpt = options.period - 1;
        days += periodOpt * DAYS_IN_PERIOD;
    }
    if (options.week) {
        const weekOpt = options.week - 1;
        days += weekOpt * DAYS_IN_WEEK;
    }
    if (options.day) {
        const dayOpt = options.day - 1;
        days += dayOpt;
    }
    return new Date(days * MILLIS_IN_DAY);
}
exports.default = {
    QUARTERS_IN_YEAR,
    PERIODS_IN_YEAR,
    DAYS_IN_PERIOD,
    DAYS_IN_YEAR,
    fromDate,
    toDate,
    convert: fromDate, // For backwards compatibility
};