JavaScript questions that don't deserve their own thread

<Custom Action Start Effect>
action = user.currentAction();
//if the scope isn't "1 enemy", action._targetIndex = -1
//otherwise, it's the index of the target, 0 or higher
if(action._targetIndex >= 0) {
  if(Math.random() <= 0.5) { //roll for redirection
    action.setTarget(origin.index()); //we change the target to origin
  }
}
</Custom Action Start Effect>

$dataSkills[x].scope // scope = 1 is for targeting 1 enemy

<Custom Passive Condition>
if(user.mp <= 0) {
    condition = true;
} else {
    condition = false;
}
</Custom Passive Condition>

randomizeVariables = function (startVariable, endVariable) {
    shuffleArray($gameVariables._data, startVariable, endVariable);
}
/* Randomize array in-place using modified Durstenfeld shuffle algorithm
    (modified to accept beginning and end within the array)
*/
function shuffleArray(array, startIndex, endIndex) {
    for (let i = endIndex; i >= startIndex; i--) {
        const j = Math.floor(Math.random() * (i + 1));
        [array[i], array[j]] = [array[j], array[i]];
    }
}

$gameVariables.setValue(20, 0); //the default value
$gameMessage.add("selection"); //it displays along with the item choice window
$gameMessage.setItemChoice(20, 3); //the user has to select a hidden item A
$gameParty._interpreter.setWaitMode('message'); //I looked things up and this was supposed to work
console.log($gameVariables.value(20)); //that's how it displays a 0 while the item choice window is still open