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Check triggerBody for existence of a property without crashing

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Hi - how do I check for the existence of a field in the triggerBody? I cannot check for null or empty as this crashes if the property actually doesnt exist. These do not work @equals(triggerBody()['partnerId'], null) or @empty(triggerBody()['partnerId']) if "partnerId" doesnt exist. I need to check as my HTTP request can occasionally not send the required property.

Any ideas?

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Building flows

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Community Power Pla... on at

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this was solved by using the @contains function as in @contains(triggerBody(), 'partnerId')

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DenisMolodtsov 317 on at

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It does not really work for me

This still fails because genius MS Flow tries to evaluate `body('Start_single_approval')['comments']` expression even if you wrap it with if(contains())

if(contains(body('Start_single_approval'), '"comments": '), body('Start_single_approval')['comments'] ,'')

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MasterOffice365 184 on at

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I also have the same issue where the contains function doesn't work checking for the existance of a property in an array. Exactly the same logic (i.e. within an If statement).

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DenisMolodtsov 317 on at

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I could not find anything that can properly check for properties to exist...

The only ugly workaround is to create 3 scopes:
Try - try to access a property that might not exist. If it does not exist - we fail and go to the next step
Catch - Run only if the previous scope fails
Finally - Run in any case

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DenisMolodtsov 317 on at

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Created request for a function that check if property exists: https://powerusers.microsoft.com/t5/Flow-Ideas/Add-an-ability-to-check-if-property-exists-in-an-object/idi-p/191908

Please, upvote if you face the same problem.

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DenisMolodtsov 317 on at

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I haven't tested it yet, but @xilef suggests using '?' approach. Seems promising to me:
if(empty(body('ApprovalByAnyDirector')?['comments']), 'None', body('ApprovalByAnyDirector')?['comments'])

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lvg 15 on at

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Tried it...even tried with not()...does not work

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Community Power Pla... on at

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Thanks @LaurenceL , exactly what I was looking for.

contains(triggerBody(), 'thing') worked great for me.

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Community Power Pla... on at

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if(empty(body('ApprovalByAnyDirector')?['comments']), 'None', body('ApprovalByAnyDirector')?['comments'])
This expression is not foolproof solution, since it will return 'None' not only when there is no comments property, but also when comments value is empty string. But for some use cases it may be the most compact.

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3tsolutions 94 on at

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I wrote a solution to handle missing properties of an object, if it helps
LINK

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