Null Values in JSON Output

[SteveODea]

I have built a power app which collects data from individuals which I ultimately want to write to a JSON out put.

The SharePoint  items which do not have data are being written to the JSON output as "" however I want to see these as null

I have tried replacing the item in the flow with the following

equals(item()?['Name'],'',null)

but this returns false.

Can anyone recommend an expression which will return null instead of ""?

Thanks

[ChristianAbata]

hi @SteveODea  please could you share an screanshot?

[abm]

Hi @SteveODea 

You can could try using empty or length expression to check the null values.

Thanks

[abm]

Hi @SteveODea 

Try to use empty

Or use the length

[SteveODea]

Hi @ChristianAbata 

So here is my flow, in which I am attempting to create a JSON file output based on a SharePoint list.

The problem is where the SharePoint data field is empty, I want to show null in my JSON file output and not "" i.e.

"CurrentAddress":{
"Line1":"High Street",

"Line2":"Big Town",
"Line3":null,
"Postcode":"X12345"}

Here is my flow and the array action. I have no idea how to construct, say, an if statement which would return null if Line3 is empty but return the data if its not...

[SteveODea]

Hi @abm 

Unfortuantely neither of these work since they require a string for the input but my SharePoint data fields are null which makes the whole thing fall over

[ChristianAbata]

hi @SteveODea  try with equals(item()?['line3'],null,'null')

[abm]

My understanding is equals only compares and return boolean.

You could try the below expression.

if(empty(trim(item()?['Line3'])),null,trim(item()?['Line3'])

[SteveODea]

Hi @ChristianAbata 

The code doesn't fail, but it doesn't do what I expect it too.

The output I am looking for on my JSON file is either null or Line 3 of the address e.g.

"Line3":null,

or

"Line3":"Big Town",

The code you provided brings back false in all cases, even where there is data in Line3 of the address

😞

[SteveODea · Accepted solution]

I have written the syntax which gives me what I want

if(equals(items('Apply_to_each')?['Line3'],null),null,items('Apply_to_each')?['Line3'])

The problem I have is that I was using the PARSE JSON action later on to check that the output conforms to a defined JSON scheme.

The problem with this PARSE JSON action is that it can't have string and null in the same line on the scheme, which means that if you have an output which can be either, the PARSE JSON step will always fail.