mauss/src/date/index.js

lightweight, modular, type-safe utilities

/** A function that returns the current date or the date passed in */
export function current(d) {
    if (d instanceof Date)
        return d;
    return d ? new Date(d) : new Date();
}
const word = {
    days: ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'],
    months: [
        'January',
        'February',
        'March',
        'April',
        'May',
        'June',
        'July',
        'August',
        'September',
        'October',
        'November',
        'December',
    ],
};
const str = (v) => `${v}`;
const pad = (v, len = 2) => str(v).padStart(len, '0');
/**
 * A function that builds a formatter
 * @see {@link format} for the default formatter
 */
export function build({ base }) {
    const method = base === 'UTC' ? 'getUTC' : 'get';
    return (date) => {
        const d = current(date);
        if (Number.isNaN(+d))
            throw SyntaxError('Invalid Date');
        const now = {
            date: () => d[`${method}Date`](),
            day: () => d[`${method}Day`](),
            month: () => d[`${method}Month`](),
            year: () => d[`${method}FullYear`](),
            hours: () => d[`${method}Hours`](),
            minutes: () => d[`${method}Minutes`](),
            seconds: () => d[`${method}Seconds`](),
        };
        const tzo = base === 'UTC' ? 0 : d.getTimezoneOffset();
        const abs = Math.abs(tzo);
        const tz = [Math.floor(abs / 60), abs % 60];
        const marker = now.hours() < 12 ? 'AM' : 'PM';
        const sign = tzo > 0 ? '-' : '+';
        const tokens = {
            D: () => str(now.date()),
            DD: () => pad(now.date()),
            DDD: () => word.days[now.day()].slice(0, 3),
            DDDD: () => word.days[now.day()],
            M: () => str(now.month() + 1),
            MM: () => pad(now.month() + 1),
            MMM: () => word.months[now.month()].slice(0, 3),
            MMMM: () => word.months[now.month()],
            YY: () => str(now.year()).slice(2),
            YYYY: () => str(now.year()),
            H: () => str(now.hours()),
            HH: () => pad(now.hours()),
            h: () => str(now.hours() % 12 || 12),
            hh: () => pad(now.hours() % 12 || 12),
            m: () => str(now.minutes()),
            mm: () => pad(now.minutes()),
            s: () => str(now.seconds()),
            ss: () => pad(now.seconds()),
            a: marker,
            p: marker,
            A: marker,
            P: marker,
            Z: () => `${sign}${tz[0]}`,
            ZZ: () => `${sign}${pad(tz[0])}${tz[1]}`,
            ZZZ: () => `${sign}${pad(tz[0])}:${tz[1]}`,
        };
        return (mask = 'DDDD, DD MMMM YYYY') => {
            const EXP = /D{1,4}|M{1,4}|YY(?:YY)?|([hHmsAPap])\1?|Z{1,3}|\[([^\]\[]|\[[^\[\]]*\])*\]/g;
            return mask.replace(EXP, ($) => {
                const exe = tokens[$];
                if (!exe)
                    return $.slice(1, $.length - 1);
                return typeof exe === 'string' ? exe : exe();
            });
        };
    };
}
/**
 * A function that takes in a `DateValue` and returns a renderer that accepts a string mask to format the date in
 * @default 'DDDD, DD MMMM YYYY'
 */
export const format = build({});
/**
 * Travel `to` a relative date `from` a point of reference
 * @returns a new Date object with the relative date
 */
export function travel({ from, to }) {
    if (Number.isNaN((from = current(from)))) {
        throw SyntaxError('Invalid Date');
    }
    const [days, fragment = '0'] = `${to}`.split('.');
    const sign = days[0] === '-' ? -1 : 1;
    const hours = Math.round(+`0.${fragment}` * 24);
    const epoch = sign * (Math.abs(+days * 24) + hours);
    return current(+from + epoch * /* 1 hour */ 36e5);
}