Dummy humanize functions in TypeScript

humanize.ts

interface TimeUnit {
    [key: string]: number;
} 

const TIME_UNITS: TimeUnit = {
    "year": 3.154e+10,
    "month": 2.628e+9,
    "week": 6.048e+8,
    "day": 8.64e+7,
    "hour": 3.6e+6,
    "minute": 60000,
    "second": 1000,
};

export function humanizeAbsolute(when: Date | number) {
    const diff = new Date().getTime() - (typeof when === 'number' ? when : when.getTime());
    for (const unit in TIME_UNITS) {
        const quotient = Math.floor(diff / TIME_UNITS[unit]);
        if (quotient > 0) {
            return `${quotient} ${unit}${quotient > 1 ? "s" : ""}  ago`;
        }
    }
    return "just now";
}

export function humanizeRelative(pastMilliseconds: number) {
    return humanizeAbsolute(new Date().getTime() - pastMilliseconds);
}

// console.log(humanizeAbsolute(new Date("2021-02-13T19:42:00Z")));
// console.log(humanizeAbsolute(new Date("2021-02-13T19:42:00Z").getTime()));
// console.log(humanizeRelative(360000)); // 1 hour
// console.log(humanizeRelative(2000)); // 2 seconds