HN Rank

    const GRAVITY = 1.8;
    const TIMEBASE = 2;
    const NO_URL_FACTOR = 0.4;
    const NON_STORY_FACTOR = 0.8;

    function calculateRank(
        score: number,
        scoreTime: Date,
        storyTime: Date,
        type: string,
        storyHasUrl: boolean,
        commentCount: number,
    ): number {
        let baseScore = score - 1; // points
        if (baseScore > 0) {
            baseScore = Math.pow(baseScore, 0.8);
        }
        const age = differenceInMinutes(scoreTime, storyTime) / 60;
        const adjustedAge = age + TIMEBASE;
        let rank = baseScore / Math.pow(adjustedAge, GRAVITY);
        if (type === "story" || type === "poll") {
            if (!storyHasUrl) {
                rank *= NO_URL_FACTOR;
            }
            rank *= calculateControFactor(score, commentCount);
        } else {
            rank *= NON_STORY_FACTOR;
        }
        // Note: Can't implement the following due to lack of data:
        // - gag-factor
        // - lightweight-factor
        return rank;
    }

    function calculateControFactor(score: number, commentCount: number): number {
        if (commentCount > 20) {
            return Math.min(1, Math.pow(score / commentCount, 2));
        }
        return 1;
    }