function timestampToWords(timestamp) {
    // Convert timestamp to milliseconds
    let milliseconds = timestamp * 1000;

    // Create a new Date object
    let date = new Date(milliseconds);

    // Get the current date
    let currentDate = new Date();
    currentDate.setHours(0, 0, 0, 0); // Reset hours, minutes, seconds, and milliseconds for comparison

    // Get the parts of the date
    let year = date.getFullYear();
    let month = date.getMonth() + 1; // Months are zero-indexed, so we add 1
    let day = date.getDate();
    let hours = date.getHours();
    let minutes = date.getMinutes();

    // Check if the date is today, tomorrow, or later
    let dateString;
    if (date.toDateString() === currentDate.toDateString()) {
        dateString = 'today';
    } else {
        let diff = (date - currentDate) / (1000 * 60 * 60 * 24);
        if (diff <= 1) {
            dateString = 'tomorrow';
        } else {
            dateString = `${year}-${month < 10 ? '0' : ''}${month}-${day < 10 ? '0' : ''}${day}`;
        }
    }

    // Construct the human-readable string
    if (dateString === 'today' || dateString === 'tomorrow') {
        return dateString;
    } else {
        return `${dateString} ${hours < 10 ? '0' : ''}${hours}:${minutes < 10 ? '0' : ''}${minutes}`;
    }
}

// Example usage
let timestamp = 1615804800; // Example timestamp for March 15, 2021 (today)
console.log(timestampToWords(timestamp)); // Output: "today"

timestamp = 1615891200; // Example timestamp for March 16, 2021 (tomorrow)
console.log(timestampToWords(timestamp)); // Output: "tomorrow"

timestamp = 1615977600; // Example timestamp for March 17, 2021
console.log(timestampToWords(timestamp)); // Output: "2021-03-17 00:00"