To calculate the difference between two dates in Years, Months, Days, Hours, Minutes, Seconds, Milliseconds using JavaScript / TypeScript

dateDifference.ts

dateDifference(actualDate, value: boolean) {
            // Calculate time between two dates:
            const date1 = actualDate; // the date you already commented/ posted
            const date2: any = new Date(); // today

            let r = {}; // object for clarity
            let message: string;

            const diffInSeconds: number = Math.abs(date2 - date1) / 1000;
            const days: number = Math.floor(diffInSeconds / 60 / 60 / 24);
            const hours: number = Math.floor(diffInSeconds / 60 / 60 % 24);
            const minutes: number = Math.floor(diffInSeconds / 60 % 60);
            const seconds: number = Math.floor(diffInSeconds % 60);
            const milliseconds: number = 
           Math.round((diffInSeconds - Math.floor(diffInSeconds)) * 1000);

            const months: number = Math.floor(days / 31);
            const years: number = Math.floor(months / 12);

            // the below object is just optional 
            // if you want to return an object instead of a message
            r = {
                years,
                months,
                days,
                hours,
                minutes,
                seconds,
                milliseconds
            };

            // check if difference is in years or months
            if (years === 0 && months === 0) {
                // show in days if no years / months
                if (days > 0) {
                    if (days === 1) {
                        message = days + ' day';
                    } else { message = days + ' days'; }
                }  else if (hours > 0) {
                    // show in hours if no years / months / days
                    if (hours === 1) {
                        message = hours + ' hour';
                    } else {
                        message = hours + ' hours';
                    }
                } else {
                    // show in minutes if no years / months / days / hours
                    if (minutes === 1) {
                        message = minutes + ' minute';
                    } else {message = minutes + ' minutes';}  
                }
            } else if (years === 0 && months > 0) {
                // show in months if no years
                if (months === 1) {
                    message = months + ' month';
                } else {message = months + ' months';}
            } else if (years > 0) {
                // show in years if years exist
                if (years === 1) {
                    message = years + ' year';
                } else {message = years + ' years';}
            }

            // To display either an object or a message in the view
           if (value === true) {
                    return r;
                }
            return message;
        }

/* Sample Output

For example, consider a user X commented/posted something on any forum / facebook on Mon Jul 30 2018 12:08:00 GMT-0400 (Eastern Daylight Time)

Difference between Tue Jul 31 2018 13:11:04 GMT-0400 (Eastern Daylight Time) and the posted time of user X comment/post in simple message is "Posted 1 day ago"

Difference between now and the posted time of user X comment/post in detail object is "0 years, 0 months, 1 days, 1 hours, 3 minutes, 4 seconds, 613 milliseconds ago"

You can view this code written only in javascript here [https://code.sololearn.com/W2zBQeA8j595]

*/