Showing results for 
Search instead for 
Did you mean: 
Frequent Visitor

How to add a new property to an object-type variable in Apply to Each?



Inside an Apply to Each loop's Data-Compose action, if I add an expression using 'addProperty' to add a dynamically created key and value (both created using the loop item data) the object variable remains empty after the loop.


An example of the addProperty withing the Data-Compose action might be:

addProperty(variables('obj_var'), item()['key'], item()['value'])

On the loop completing the Data-Compose action Output contains an array of objects each containing a single property, rather than my hoped for single object containing the comma seperated list of key:value property pairs eg.

{ "name":"John", "age":30, "car":null } 


Is it possibe to add dynamically created key:values using addProperty to an object variable within a loop?



Community Support
Community Support

Hi @euanjfc,


Could you please share a screenshot of the configuration of your flow?

Could you please share more details about your scenes?


I have made a test on my side and I couldn't find a way to add dynamically created key:values using addProperty to an object variable within a loop.


Please share more details so we would try to provide a proper workaround for you.


Best regards,




Image of example flow  below. The addProperty expression is -


Example flow


and the final Compose output when run shows the empty object variable and the Compose output with an array of objects:

{} [{"key1":"value1"},{"key2":"value2"}]


The addProperty()  returns a new object.  It doesn't update the variable referenced by the first object.  You have to assign a second object variable the output from addProperty(variable('obj_var'), item().item.key, item().item.value).  Then assign that second variable back to 'obj_var'.  Flow won't let you assign directly to the same var.

Here is a screen shot of my flow.  Configuration is the variable I want to get the new properties. (basically the same as your obj_var)


2019-02-16 14_35_26-.png

This is great, but what are the bottom two variable actions? Append to array doesnt work if you have defined an object...

Can you please expand and maybe explain a little more? @JeffCGrd 

I am doing it the other way round. In a loop of items that I want to append to my object, I'm first using "union" function together with the "addProperty" and then "Set variable" so that ma unioned object is updated:2019-03-01_11h51_53.pngThe "union" operation looks as below:

union(addProperty(variables('var_TempSubscInstanceName_dict'),item()?['Id'],item()?['Name']), variables('var_SubscInstanceName_dict'))

So in the end it is joining together a new object created by "addProperty" and the existing object initiated as variable.

Next I am simply updating (Set variable) my object with the result of the union operations.







Sorry for the late response.  My companies spam filter was catching these notifications.

@LorenEdgell_HEI wrote:

This is great, but what are the bottom two variable actions? Append to array doesnt work if you have defined an object...

Can you please expand and maybe explain a little more? @JeffCGrd 

They are just "Set Variable".  The variables are initialized as Object type.  AddProperty() returns an object and it is assigned to tmpObj.  Then because I want the final values in the configuration variable, I set configuration to the value in tmpObj.

I know this was written 4 years ago, but I hope you might see this!  Do you actually need the union() command?  If addProperty() returns a new object with the new property added to it, doesn't that already achieve what you're trying to do?

Helpful resources


Celebrating the May Super User of the Month: Laurens Martens

  @LaurensM  is an exceptional contributor to the Power Platform Community. Super Users like Laurens inspire others through their example, encouragement, and active participation. We are excited to celebrated Laurens as our Super User of the Month for May 2024.   Consistent Engagement:  He consistently engages with the community by answering forum questions, sharing insights, and providing solutions. Laurens dedication helps other users find answers and overcome challenges.   Community Expertise: As a Super User, Laurens plays a crucial role in maintaining a knowledge sharing environment. Always ensuring a positive experience for everyone.   Leadership: He shares valuable insights on community growth, engagement, and future trends. Their contributions help shape the Power Platform Community.   Congratulations, Laurens Martens, for your outstanding work! Keep inspiring others and making a difference in the community!   Keep up the fantastic work!        

Check out the Copilot Studio Cookbook today!

We are excited to announce our new Copilot Cookbook Gallery in the Copilot Studio Community. We can't wait for you to share your expertise and your experience!    Join us for an amazing opportunity where you'll be one of the first to contribute to the Copilot Cookbook—your ultimate guide to mastering Microsoft Copilot. Whether you're seeking inspiration or grappling with a challenge while crafting apps, you probably already know that Copilot Cookbook is your reliable assistant, offering a wealth of tips and tricks at your fingertips--and we want you to add your expertise. What can you "cook" up?   Click this link to get started:   Don't miss out on this exclusive opportunity to be one of the first in the Community to share your app creation journey with Copilot. We'll be announcing a Cookbook Challenge very soon and want to make sure you one of the first "cooks" in the kitchen.   Don't miss your moment--start submitting in the Copilot Cookbook Gallery today!     Thank you,  Engagement Team

Announcing Power Apps Copilot Cookbook Gallery

We are excited to share that the all-new Copilot Cookbook Gallery for Power Apps is now available in the Power Apps Community, full of tips and tricks on how to best use Microsoft Copilot as you develop and create in Power Apps. The new Copilot Cookbook is your go-to resource when you need inspiration--or when you're stuck--and aren't sure how to best partner with Copilot while creating apps.   Whether you're looking for the best prompts or just want to know about responsible AI use, visit Copilot Cookbook for regular updates you can rely on--while also serving up some of your greatest tips and tricks for the Community. Check Out the new Copilot Cookbook for Power Apps today: Copilot Cookbook - Power Platform Community.  We can't wait to see what you "cook" up!    

Welcome to the Power Automate Community

You are now a part of a fast-growing vibrant group of peers and industry experts who are here to network, share knowledge, and even have a little fun.   Now that you are a member, you can enjoy the following resources:   Welcome to the Community   News & Announcements: The is your place to get all the latest news around community events and announcements. This is where we share with the community what is going on and how to participate.  Be sure to subscribe to this board and not miss an announcement.   Get Help with Power Automate Forums: If you're looking for support with any part of Power Automate, our forums are the place to go. From General Power Automate forums to Using Connectors, Building Flows and Using Flows.  You will find thousands of technical professionals, and Super Users with years of experience who are ready and eager to answer your questions. You now have the ability to post, reply and give "kudos" on the Power Automate community forums. Make sure you conduct a quick search before creating a new post because your question may have already been asked and answered. Galleries: The galleries are full of content and can assist you with information on creating a flow in our Webinars and Video Gallery, and the ability to share the flows you have created in the Power Automate Cookbook.  Stay connected with the Community Connections & How-To Videos from the Microsoft Community Team. Check out the awesome content being shared there today.   Power Automate Community Blog: Over the years, more than 700 Power Automate Community Blog articles have been written and published by our thriving community. Our community members have learned some excellent tips and have keen insights on the future of process automation. In the Power Automate Community Blog, you can read the latest Power Automate-related posts from our community blog authors around the world. Let us know if you'd like to become an author and contribute your own writing — everything Power Automate-related is welcome.   Community Support: Check out and learn more about Using the Community for tips & tricks. Let us know in the Community Feedback  board if you have any questions or comments about your community experience. Again, we are so excited to welcome you to the Microsoft Power Automate community family. Whether you are brand new to the world of process automation or you are a seasoned Power Automate veteran - our goal is to shape the community to be your 'go to' for support, networking, education, inspiration and encouragement as we enjoy this adventure together.     Power Automate Community Team

Hear what's next for the Power Up Program

Hear from Principal Program Manager, Dimpi Gandhi, to discover the latest enhancements to the Microsoft #PowerUpProgram, including a new accelerated video-based curriculum crafted with the expertise of Microsoft MVPs, Rory Neary and Charlie Phipps-Bennett. If you’d like to hear what’s coming next, click the link below to sign up today!  

Tuesday Tip | How to Report Spam in Our Community

It's time for another TUESDAY TIPS, your weekly connection with the most insightful tips and tricks that empower both newcomers and veterans in the Power Platform Community! Every Tuesday, we bring you a curated selection of the finest advice, distilled from the resources and tools in the Community. Whether you’re a seasoned member or just getting started, Tuesday Tips are the perfect compass guiding you across the dynamic landscape of the Power Platform Community.   As our community family expands each week, we revisit our essential tools, tips, and tricks to ensure you’re well-versed in the community’s pulse. Keep an eye on the News & Announcements for your weekly Tuesday Tips—you never know what you may learn!   Today's Tip: How to Report Spam in Our Community We strive to maintain a professional and helpful community, and part of that effort involves keeping our platform free of spam. If you encounter a post that you believe is spam, please follow these steps to report it: Locate the Post: Find the post in question within the community.Kebab Menu: Click on the "Kebab" menu | 3 Dots, on the top right of the post.Report Inappropriate Content: Select "Report Inappropriate Content" from the menu.Submit Report: Fill out any necessary details on the form and submit your report.   Our community team will review the report and take appropriate action to ensure our community remains a valuable resource for everyone.   Thank you for helping us keep the community clean and useful!

Users online (4,919)