throttle

throttle

[4:20:11 PM] Dmitry Polovka: what's the purpose of debouncer/throttle? Just to debounce single function for ...ms, and if you will debounce same func twice, it will be called twice? 

 Or for example if 

 function x is debounced for 500ms
 after 200ms... function x is debounced for 500ms once again
 it will be called once after 500ms, and will not be added as second function call?
[4:32:55 PM] @Касперский: There are two strategies for debounce and throttle, but what common is that original function will never be called more than once in X ms no matter how many times you call throttle / debounced function.

Throttle:

One of the strategies is to call immediately on throttle function call (e.g. with 500ms), called "leading":
throttle function called at 0ms:   original function called
throttle function called at 100ms:   nothing
throttle function called at 400ms:   nothing
throttle function called at 600ms:   original function called

Another is to call after, called "tailing":
throttle function called at 0ms:   nothing
throttle function called at 100ms:   nothing
throttle function called at 400ms:   nothing
timer hit 500ms:   original function called
throttle function called at 600ms:   nothing
timer hit 1100ms:   original function called

Subsequent calls to throttle during X ms period does nothing and function will be called only once.

Debounce:
Debounce is similar, except original function will be called X ms after LAST call to debounce function, not like with throttle where original function is called X ms after FIRST throttle function call
[4:34:11 PM] @Касперский: Check:
https://lodash.com/docs#throttle
https://lodash.com/docs#debounce