How to implement the temporary save function when writing a post

Hello.

For me, the function that can be seen in the hash code,

Saving temporarily...

I'd like to implement the function.

1.

I think the principle of implementing this function is

 1. Count a certain amount of time in the keyup event and temporarily save it to DB if no input occurs
 2. SetInterval() temporarily stored in DB every certain time

I think of a way to do that.

2.

 Also, I wonder where you save it.

 1. How to save to a normal DB
 2. How to use redis and memcached
 3. How to use localStorage

Is there any example of hash code that I think is implemented? Also, please help me with which method can be optimized for items 1 and 2.

ps. The environment in which you want to use the above function is the screen where you create a post like a hash code. However, there are more inputs that you create on one screen. ( input, textarea, file )