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Fail to read an array returned from javascript function on a web page in dekstop power automate

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Posted on by boomcheesebuger

I have the following javascript function in my flow (desktop power automate):

function ExecuteScript() { 
 	var aTags = document.getElementsByClassName("gridviewlist");
 	var tdTags = aTags[0].getElementsByTagName("td");
 	var searchText = "%CurrentFood%";
 	
 	for (var i = 0; i < tdTags.length; i++) {
 		 if (tdTags[i].textContent.toLowerCase() == searchText.toLowerCase()) {
 			 nutrientName = tdTags[i+3].textContent;
 			 nutrientUnit = tdTags[i+4].textContent;
 		 }
 	}
 	
 	const nutrientNU = [nutrientName, nutrientUnit];
 	return nutrientNU;
}

I want to return an array which has 2 items. However, when I look at in the Flow Variables, it shows the following:

How do I return the 2 items from javascript function so that I can get them in the flow?

Thanks,
Andy

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Power Automate Desktop

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Pstork1 69,661 Most Valuable Professional on at

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Your javascript function returns an object with two properties, not an array. You should be able to access the value of the two properties directly from your object. It should be something like

%NutrientNU[NutrientName]% %NutrientNU[nutrientUnit]%
boomcheesebuger 9 on at

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I have tried your answer, but I have the following error:
Pstork1 69,661 Most Valuable Professional on at

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Sorry, I forgot to put the single quotes around the property names.

%NutrientNU['NutrientName']% %NutrientNU['nutrientUnit']%

That should work if the javascript is returning the object with named properties. If the values are being returned as an object and property names aren't included I'm not sure how you reference the values. But it will be some variation on the code above.
boomcheesebuger 9 on at

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Following your hint, I have changed the javascript function as follows:

I still got the following error:
Pstork1 69,661 Most Valuable Professional on at

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Try adding the single quotes around the property names in the Javascript also.
waynewalls 74 on at

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The documentation for PAD indicates that the result returned by the Run JavaScript Function action is a text value. The "[object Object]" returned from your function is likely the result of the default toString() method called on nutrientNU.

I also encounter "[object Object]" when I try and return a text value that is null or undefined.

Try returning a string from your function. Something like:

return nutrientNew + ", " + nutrientUnit;

Then use PAD's text actions to parse it once you have it back inside the flow.
AndyStewart 18 on at

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Try using JSON.stringify(variable) to convert it to a string and return that...
waynewalls 74 on at

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Hi @AndyStewart

Using JSON.stringify() was my first inclination too. Except when I found out it also returned the string "[object Object]". At that point I was under a deadline and just had to make something work.

Subsequently, based on the MDN documentation I found that JSON.stringify() does not always return a string. When something is undefined it returns undefined. Which, I infer, is serialized somewhere in the PAD/extension processing to the string "[object Object]".

I now use something like
if (variable_to_be_returned === undefined) return ("undefined") else return (JSON.stringify(variable_to_be_returned)

As an aside, the MDN docs indicate that there are other instances when JSON.stringify() does not return a string or accurately reflect the true result (e.g., NaN is returned as "null"). These do not apply to my current situation but might provide useful debugging information for others.