Cannot initialize JSON object with initialize variable

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Posted on by FL-19021510-0

My power app button passes one json object among 6 texts, and I wanted to initialize this in power automate. In the power App V2 trigger, I created a text input called varOptionalFields.
I then proceeded to add a initialize variable with the code:

json(triggerBody()?['varOptionalFields'])

Now when running the power App, the json object does get outputed by the power apps trigger as seen by:

{"Beschreibung_2":"test","Beschreibung_3":"tet","Beschreibung_4":"tes","Beschreibung_5":"test","Beschreibung_6":"test","Beschreibung_7":"test"}

But the initialize variable fails and i get this error message:

Action 'Initialize_variable' failed: Unable to process template language expressions in action 'Initialize_variable' inputs at line '0' and column '0': 'The template language function 'json' expects its parameter to be a string or an XML. The provided value is of type 'Null'. Please see https://aka.ms/logicexpressions#json for usage details.'.

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Pstork1 69,556 Most Valuable Professional on at

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When you pass a JSON value in the trigger it comes in as text. You need to use a Parse JSON action in Power Automate to turn it back into valid JSON with a schema. I do this frequently when passing large numbers of parameters.

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11manish 3,333 on at

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Make it null-safe

Use:

json(coalesce(triggerBody()?['varOptionalFields'], '{}'))

Ensure Power Apps sends JSON as STRING

Use:

JSON(varOptionalFields, JSONFormat.Compact)

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