Beside copying from w3fools, this "solution" is neither clever nor best practice - it is inherently wrong.
Bitshifting by zero will have a sideeffect on large numbers, especially negative ones.
The output will be a positive number that is way too small and not the result of the calculation anymore. Bitshifting using >>> will replace the first bit with a zero, converting negative numbers into positive ones.

append one zero to a, I wrote 10.000, not 1.000.

why do you think so. i used recursion for my function and its was completed really fast even with a = 1000 and b=1;

Anyone else is wondering why some "clever" solutions in javascript clutter memory by using the map function to slice k array items at the given index? What a waste of RAM! Not very clever imho...

I love this solution very much, it is very neat, clean and effective!

a is the accumulator and [_,d] is the inner array of lst, spread to the variables _ and d. Why _ as var-name? Just because its unused.
the 1 is the initial value of the accumulator.

the performance of this recursion is very bad, for example a = 10000 and b = 1

like this approach, as the directory can be passed as argument :) neat solution, also the regex

//==   Manually  notification   ==\\
\\== Please read the pose above ==//

+1 for trollface

You replace it with char \0 (Null-character) instad of an empty string.
This website is for losers LOL! results in Th\0s w\0bs\0t\0 \0s f\0r l\0s\0rs L\0L!.