JS | 位元運算 Bitwise Operator

The following is my solution regarding a CodeSignal Problem addTwoDigits

1st Draft (61 Chars) makes use of reduce

addTwoDigits=n=>
  (""+n).split("").reduce((x,y)=>
    x+Number(y)
  ,0)

2nd Draft (49 Chars) deploys a recursive skill

f = addTwoDigits = n => n<10 
  ? n
  : n%10 + f(Math.floor(n/10))

It turns out I ignored the constraints that the number has only 2 digits… but I learnt a new trick from the best solutionsss

addTwoDigits = n => n%10 + n/10|0

After some researches, there are quite some magical uses for the | bitwise operator, e.g. x|0 can function as:

1. Math.floor(x) for postive x

2. parseInt(x) for string x

3. 0 for many special x (NaN, Infinity, null, undefined, [], {} …)