How to map new property values to an array of JSON objects?

Question

I'm reading back record sets in an express server using the node mssql package. Reading back the values outputs an array of Json objects as expected.

Now I need to modify the Email propoerty value of each Json object. So I tried looping through the recordset and changing the value at each index:

            var request = new sql.Request(sql.globalConnection);
            request.input('p_email', sql.VarChar(50), userEmail);
            request.execute('GetDDMUserProfile', function(err, recordsets, returnValue) {      

               for (var i = 0; i < recordsets.length; i++){
                    recordsets[i].Email = "[email protected]";

                }

                console.log(recordsets);

            });

But instead of modifying the Emailvalue of each Json object, this code just appends a new email property to the last Json object.

How can you map new property values to an array of JSON objects?

Example output: An example of the output is shown below, where a new Email property has been added to the end of the array instead of changing each existing property value:

[  
   [  
      {  
         ID:[  
            4
         ],
         UserName:"Brian",
         Email:"[email protected]"
      },
      {  
         ID:[  
            5
         ],
         UserName:"Brian",
         Email:"[email protected]"
      }      
   Email:'[email protected]' ]
]

jeffdill2 · Accepted Answer · 2016-11-10 14:09:04Z

1

The issue here is that your dataset appears to not be an array of JSON objects but, rather, an array of arrays of JSON objects. If you know for certain that you'll always have only one array in the top-most array, then you can solve the problem like this:

recordsets[0][i].Email = "[email protected]";

to always target the first array in the top-most array. However, if the top-most array could potentially have more than one array, that'll be a different kind of issue to solve.

answered Nov 10, 2016 at 14:09

jeffdill2

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5 Comments

Brian Var Over a year ago

So I tried this previously recordsets[0][i].Email = "[email protected]"; and it only modifies the Email value of the first json object. All subsequent object's Email values stays the same. For example hastebin.com/tanifucitu.pl Any ideas why that is?

jeffdill2 Over a year ago

It's because you're doing recordsets.length in your for loop. Since recordsets only has one element – the array of JSON objects – the for is only looping once. You'll need to change it to recordsets[0].length to get the actual count of the JSON objects in the interior array.

Beebee Over a year ago

@BrianJ as in the original answer above, you're using an array of arrays. So first array only has 1 entry. In your for loop if you don't change i < recordsets.length to i < recordsets[0].length your loop only runs once. Hope that's clear?

jeffdill2 Over a year ago

@Beebee jinx. :-)

Brian Var Over a year ago

yep clear as day, I needed to change the index in the loop because of the nested arrays.

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