CODEWITHSUNDEEP
javascriptarrays
Christopher
Christopher

Reputation: 35

How can this function be returning undefined?

This seems so simple but I just don't get it. Why when I pass b and c through the function below, and the if statement returns true, and I use a return statement, I get undefined?

function stockList(arr1, arr2){
  arr1.forEach(function(elB){
     for (var elC in arr2){
       if (elB.charAt(0) === arr2[elC]){
        return "hello"
       }
     }
  })
}

b = ["ABAR 200", "CDXE 500", "BKWR 250", "BTSQ 890", "DRTY 600"]
c = ["A", "B"]

stockList(b,c)

I expect the result to be "hello" but I get undefined. I have a feeling I'm going to hit my head and go "doh" when I discover the problem. Thanks for any response.

Upvotes: 1

Views: 45

Answers (2)

Jack Bashford
Jack Bashford

Reputation: 44107

forEach doesn't return anything. Use two for loops, and maybe add a catch-all return at then end of the function too:

function stockList(arr1, arr2) {
  for (var elB in arr1) {
    for (var elC in arr2) {
      if (arr1[elB].charAt(0) === arr2[elC]) {
        return "hello"
      }
    }
  }
  return "goodbye";
}

b = ["ABAR 200", "CDXE 500", "BKWR 250", "BTSQ 890", "DRTY 600"]
c = ["A", "B"]

console.log(stockList(b, c));

Upvotes: 1

jsgoupil
jsgoupil

Reputation: 3997

You are returning hello from an inner function: the forEach. If you want to return hello from the main function, do not use a forEach, use a simple for loop.

Upvotes: 0

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