arrayCounter, 'string', 'number', 'undefined'

Question

Hello!

I am supposed the create a function that takes in an array, and the function must return the length of the items in the array.

I have to use an if() to check if any of the values in the array are either (string, number, undefined). I believe the task is to check If any of the values in the array are one of the 3, if I there is a match, I must return 0 to the console.

I have managed to get the length of the array, but I cant think of the right if () test to check for these values. I have always thought the only way to go through an array is with a for loop, but the assignments is expecting an if()

1) How can I conduct this test for these 3 values in the array?

2)When I do a console.log(typeof array);it returns 'Object', if the parameter is storing an array, shouldn't the web console say Array? Yes, I know arrays are objects, but I am new to using web console, so I just want to confirm. Thanks!! <!DOCTYPE html> <html lang="en"> <head> <title>JavaScript Foundations: Functions</title> <style> html { background: #FAFAFA; font-family: sans-serif; } </style> </head> <body> <h1>JavaScript Foundations</h1> <h2>Functions: Return Values</h2> <script>

function arrayCounter(array)
{
    if (  typeof array === 'string' ||  'number' || 'undefined')
    {
    return 0;

    }
return array.length


}   
console.log(arrayCounter(["apple", "oranges", "avocado"]));;
</script>

</body> </html>

Answer 1 · 2014-06-03T01:20:19Z

June 3, 2014 1:20am

You are not supposed to check the elements of the array. An array is a single argument to this function. You have to check if that argument is in fact an array, or rather, you have to check that it's not a string, number or undefined.

And when checking multiple conditions in an if statement, you have to do each check separately:

function arrayCounter(array) {
    if (  typeof array === 'string' || typeof array === 'number' || typeof array === 'undefined') { // you have to repeat the whole expression, not just the value you're comparing with
        return 0;
    }
    return array.length;
}

Answer 2 · 2014-06-03T16:45:16Z

June 3, 2014 4:45pm

Thanks Dino for your help. Just out of curiousity if I wanted to put some elements in my array and pass it to the arrayCounter so that the alert ('this is not a valid type') in the if() gets trigerred how can I do that? I tried with the code below, but .... Cheers!

<!DOCTYPE html>
<html lang="en">
  <head>
    <title>JavaScript Foundations: Functions</title>
    <style>
      html {
        background: #FAFAFA;
        font-family: sans-serif;
      }
    </style>
  </head>
  <body>
    <h1>JavaScript Foundations</h1>
    <h2>Functions: Return Values</h2>
    <script>
      function arrayCounter(array) 
      {
    if (  typeof array === 'string' || typeof array === 'number' || typeof array === 'undefined') { // you have to repeat the whole expression, not just the value you're comparing with
        alert("It is an invalid type");
        return 0;
    }
    return array.length;
    }

console.log (arrayCounter(["apple", "orange"]));



    </script>
  </body>
</html>

Answer 3 · 2014-06-03T16:53:45Z

June 3, 2014 4:53pm

hahaha! right!! and in that case, the alert should say ' it is a valid type'. Thanks a million Dino!

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arrayCounter, 'string', 'number', 'undefined'

3 Answers

Dino Paškvan

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Dino Paškvan

Dino Paškvan

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