Compose actions inside apply to each steps in Microsoft Flow

Today I came across  a weird feature in Microsoft Flow. I collected a list of files from SharePoint and I was setting a Compose with the title of my files. In the run history each file was listed and I was quite happy with this. Inside the apply to each step can use this value.

But what if I use this outside the Apply to each after the Apply to each has finished. To my surprise I was getting an array back.

My first thought was: “That is annoying. That can’t be right!”

But you could use this to filter your arrays.

With the condition set to:

startsWith(outputs('Compose_-_File_name'),'t')

This now resulted in an array just giving me the files starting with the letter t.

However I found that the array returned looked like this:


[null,"text","test2",null,"tf78062375",null,null,null,null,null]

Concurrency

It looks like the compose actions inside the apply to each steps are created as an array. Why?

Although by default the Concurrency is switched of on every Apply to each step. It is possible to enable this. To make sure that things don’t go wrong and data would get mixed up, an array of compose actions is created.