Read value from field that is sometimes not present.

[Default]

Hi folks,

In DevOps, we've created the "change" tag, and I've set up a flow that organizes all work items with that tag neatly on a change and release calendar. Sometimes, someone forgets to fill in the target date, and then my flow gets stuck because that's precisely the date when that change should appear on the calendar.

When the target date is filled in, the flow can also read it: "Get details of work item" outputs:

"Microsoft_VSTS_Scheduling_TargetDate": "2024-06-27T22:00:00Z",

but if the target date is not filled in, there is no line with "Microsoft_VSTS_Scheduling_TargetDate" in the output, so my flow can't read the value because the field isn't there.

How can I make my flow check whether the target date field is filled in?

Thnx in advance!

[rzaneti · Accepted solution]

Hi @Default ,

If your use case can handle nulls for the date, you can just add a question mark before the property that you are trying to access. If not, you can use an if expression to set a default variable if the property is missing.

For further reference on the topics discussed in the solution below, check these blog posts that I recently wrote:

- Object data type in Power Automate: http://digitalmill.net/2024/02/08/object-data-type-in-power-automate/ 

- Writing expressions in Power Automate: http://digitalmill.net/2024/02/27/writing-expressions-in-power-automate/ 

Let's assume that I have an object like this:

And I want to extract data about the "delivery_date" property, which does not exist in this object. I can use the following approach, which will assign a null value to my string variable:

The flow will not fail, as the "delivery_date" property will be accessed only if it exists, but variable will be empty, which can be a problem for some use cases. If you need to prevent the nulls and set a default value in case of the user forgets to include it, you can use an expression like this:

Expression content: if(contains(variables('order'), 'delivery_date'),variables('order')['delivery_date'], utcNow())

We are using an if statement, evaluating with the contains() expression if the variable "order" contains the property "delivery date" (in red). If yes, we return it (in blue); if not, we just use the current date/time as default (in green). Here is the output of the expression (current date/time, as there is no "delivery_date" property in the object:

Let's now change the object to test the expression with a delivery_date:

And this is the output:

Let me know if it works for you or if you need any additional help!

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[Default]

Hi Rzaneti,

Perfect! Works flawlessly! Thanks a lot!