CODEWITHSUNDEEP
javascriptarrays
Covert
Covert

Reputation: 491

Why if condition fails to execute?

I have written a function showWorthSum() to return the sum of an array. It does but I have also put a condition if an element of an array is a number then it should be calculated only and rest should be skipped but still, it goes inside the if block in case of NaN and makes the whole result NaN. Why ? 

function addWorth()
{    
    var table1= document.getElementById("tableNetWorths");

    var rowCount1= table1.rows.length;

    //var row1= table1.insertRow(rowCount1);

   var arr= [];

   for(var count = 0; count < rowCount1; count++)
   {    
        arr.push(table1.rows[count].cells[1].innerHTML);          
   }

   arr.shift();
   return arr;
} 

function showWorthSum()
{
    var returnedArr= addWorth();

    //returnedArr.push(addWorth());

     totalWorth= 0;

    var arrCount= returnedArr.length;

    for(var count = 0; count < arrCount; count++)
    {    
            if(typeof(parseInt(returnedArr[count])) == 'number')
            {
                totalWorth= parseInt(totalWorth)+ parseInt(returnedArr[count]); 
                //document.write(returnedArr[count]);

            }
    }

    return parseInt(totalWorth);
}

array: {100.200. 'asdadasd', 322, 22}

Button:

<button class="btn btn-primary" onclick="document.write(showWorthSum())" type="button">Show Sum</button>

Upvotes: 0

Views: 68

Answers (2)

Ajay Gupta
Ajay Gupta

Reputation: 31

Instead of "typeof(parseInt(returnedArr[count])) == 'number'", you can use isFinite(returnedArr[count]).

isFinite('foo')
false

isFinite('10')
true

isFinite(10)
true

isFinite('898.0900')
true

Upvotes: 2

nick zoum
nick zoum

Reputation: 7305

Try this instead isNaN(parseInt(returnedArr[count])) === false

Although NaN by definition is Not A Number, typeof NaN is number

So to check if a variable is a number use isNaN(value) === false or !isNaN(value)

Examples:

  • isNaN(5) => false
  • isNaN("5") => false
  • isNaN("-5") => false
  • isNaN(true) => false
  • isNaN(false) => false
  • isNaN({}) => true
  • isNaN(NaN) => true
  • isNaN("test") => true
  • isNaN("5test") => true
  • isNaN("test5") => true

So you could also use !isNaN(returnedArr[count]) to make it shorter

Upvotes: 1

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