JS Make function object return

Question

I am creating a function object. However when I run this object it returns undefined.
For instance, in this JSFiddle example, when I try alert(test(8)), the function runs and returns 13 but when I create a Function object, 'alert(func(8))' returns undefined.

<button onclick="start()">Start Test</button>

<script>

    function test(num) {
        alert("running...");
        return num + 5;
    }

    function start(){
        alert(test(8));

        var func = new Function("num", "test(num)");
        alert(func(8)); 
    }

</script>

Gaurang Tandon · Accepted Answer · 2014-09-26 10:56:27Z

5

Because in your second func, you are not returning the value of test(num)

function test(num) {
  alert("running...");
  return parseInt(num) + 5;
}

function start(){
  alert(test(8));

  // return the value obtained on calling test(num)     <------------
  var func = new Function("num", "return test(num)");
  alert(func(8));
}

start();

edited Sep 26, 2014 at 10:56

answered Mar 10, 2014 at 7:08

Gaurang Tandon

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2 Comments

Gaurang Tandon Over a year ago

@NevilleNazerane Ok, nice you did. Could you please accept my answer if it helped. Thank you!

Neville Nazerane Over a year ago

Well frankly I found out the exact same solution before looking at your answer. However even thought it did not help it was perfect. I will accept it as far as stackoverflow allows me to do so.

Neville Nazerane · Accepted Answer · 2014-03-10 07:11:09Z

0

I found a solution. When I checked the value of the variable func in the console I found I would need to return the function like this JSFiddle. I needed to use var func = new Function("num", "return test(num)") instead of var func = new Function("num", "test(num)")

answered Mar 10, 2014 at 7:11

Neville Nazerane

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