CODEWITHSUNDEEP
javascriptreturnreturn-value
samlandfried
samlandfried

Reputation: 821

This variable is an array. Why is it returning undefined?

This is a partial attempt at solving the Eloquent Javascript challenge in Chapter 4, A List. theArray returns undefined, but if I just print its value it is what I would expect (An array of values). Why does it return undefined?

var obj = {"value":"C","rest":{"value":"B","rest":{"value":"A"}}};

var theArray =[];

var listToArray = function(list) {
  theArray.push(list.value);
    if(list.rest !== undefined) {
      listToArray(list.rest);
    } else return theArray; //console.log(theArray); returns the expected value
}

console.log(listToArray(obj));

Upvotes: 2

Views: 530

Answers (1)

Rajaprabhu Aravindasamy
Rajaprabhu Aravindasamy

Reputation: 67207

You have to return the recursive call,

 if(list.rest !== undefined) {
      return listToArray(list.rest);

DEMO

If you do not return the recursive call, then the array which is from the final function stack will not be returned instead undefined will be returned.

Upvotes: 3

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