Javascript Recursive function and ||

Asked Mar 06 '16 at 19:39

Active Mar 06 '16 at 19:47

Viewed 29 times

I am having a hard time wrapping my head around one example from Elequentjavascript.

In the else statement there you will find || operator. One of the expressions will be executed but which one? I know it is the one that is set to true, but I cant seem to figure out how it is being evaluated.

function findSolution(target) {
  function find(start, history) {
    if (start == target)
      return history;
    else if (start > target)
      return null;
    else
      return find(start + 5, "(" + history + " + 5)") ||
             find(start * 3, "(" + history + " * 3)");
  }
  return find(1, "1");
}

console.log(findSolution(24));

As I understand short-circuit || operator both sides will be evaluated. But how does it choose the right one?

edited Mar 06 '16 at 19:43

asked Mar 06 '16 at 19:39

K N

1

One *or both* of the recursive calls will be made, not just one. – Pointy Mar 06 '16 at 19:41
Both when the first fails ??? And only one if the left expression returns true? – K N Mar 07 '16 at 08:22

Javascript Recursive function and ||

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