exactly, but that was not clear until I hit this. I assumed "return" meant stop processing the rest of the line. Sort of like this in Javascript, I just assumed returned meant to return, not continue...

// a = b && c = dfunctionfoo(a, b, c, d) {
    let res = a === b ? 1 : 0; // a = bif (res === 0) { // left side of &&return res // return left side
    }
    res = c // res && c
    res = res === d ? 1 : 0// res = dreturn res
}