javascript - A somewhat painful triple-nested ternary operator

Question

I went looking through Raphael.js's source code to find out how he converted RGB values to HSB. I found out the function he did it in and I was in the process of converting it to Python when I bumped into this nice triple-nested ternary operator:

H = (C == 0 ? null :
    V == r ? (g - b) / C :
    V == g ? (b - r) / C + 2 :
             (r - g) / C + 4
    );

It threw me for a loop because Python doesn't have the same kind of ternary operator that Javascript does. I spent a while looking over it and eventually hashed this somewhat saner code (using only if/else) out of it:

if (C == 0) {
    H = null;
} else {
    if(V == r) {
        H = (g - b) / C;
    } else {
        if(V == g) {
            H = (b - r) / C + 2;
        } else {
            H = (r - g) / C + 4;
        }
    }
}

Was my interpretation correct? I'm only asking this because if it isn't correct, I'm faced with a lot of debugging. So. Did I "get it"?

question from:https://stackoverflow.com/questions/10526739/a-somewhat-painful-triple-nested-ternary-operator

Answer 1

To my personal taste, a carefully aligned nested ternary beats the if-else mess:

const H =
  C == 0 ? null            :
  V == r ? (g - b) / C     :
  V == g ? (b - r) / C + 2 :
           (r - g) / C + 4 ;