Calculate time ago / days ago from javascript dates that had to be converted to string

Due to limitations with next js, data could not be passed to client without being converted to string.

So date obtaned from database is is now a string:

 Past date as string is:   20200802016944990

I use new Date() to get the current date and convert it to string as well (Notice T is missing from my string date)

Present date as string is: 20200805013945088

In both cases, I the code below to convert to string

.toISOString().replace(/[^0-9]/g, ""); 

If these were not strings, its simple as date1 – date 2.

How to get mins/ hours/ days ago from past date and present date which are now strings?

I am using React js and Next js. I do not want to install a library like moment js.

Answer

Another approach is instead convert it to ISOstring, would be convert it to milliseconds with getTime() (it returns a number), and then would be easir to recover date and get the info you want (day, hours, minutes, etc..)

const dbDate = new Date().getTime();

console.log('getTime value =>', dbDate);

const parsedDate = new Date(dbDate);

console.log('parsed date =>', parsedDate);

console.log('Date =>', parsedDate .getDate());
console.log('Hours =>', parsedDate .getHours());
console.log('Minutes =>', parsedDate .getMinutes());

//Once you get the dates, you can do the date calculate, like:

//Get 1 day in milliseconds
var one_day=1000*60*60*24;

const date1 = new Date('9/9/2020').getTime(); //JUST AN EXAMPLE
const date2 = new Date('10/9/2020').getTime(); //JUST AN EXAMPLE

const diffTime = Math.abs(date2 - date1);

const diffDays = Math.ceil(diffTime / one_day); 

console.log(diffTime + " milliseconds");
console.log(diffDays + " days");