How to add Microsoft Planner checklist items dynamically using Power Automate?

While answering questions in the Power Automate forum, I’ve seen one that pops up once in a while. How to add checklist items dynamically to Microsoft Planner? 

However, there’s a better way so let’s explore it today.

Strategy

The strategy is simple. Keep “somewhere” the template with the checklist items you want to add to a task. This way, we can have a list in Excel or a SharePoint list containing all our checklist items. By doing this, we can quickly modify the text, add or remove them, and you don’t need to change the Flow to do it.

If you add the checklist items individually, you will see something like this:

This works for a few, but we need to generate the checklist items dynamically when you start getting many items. To do that, let’s see the structure that Flow requires. To do that, press the toggle switch:

We’ll see our items but in a JSON array.

This is the string and the structure that we need to generate. So let’s see how to do it.

The Flow

The Flow has 3 main parts.

1. Get the checklist items from SharePoint.
2. Build the checklist JSON array
3. Updates the task with the checklist items

Let’s build it, but first, the global overview of what you can expect.

We’re using the “Scope action” to aggregate the actions together. 

Get the checklist items from the SharePoint List.

As mentioned before, you can have any data source for this. The important part is storing the checklist items where you can edit them quickly without changing the Flow.

The SharePoint list is quite simple but does the job nicely.

The only thing I did is add a constraint so that all the IDs are unique.

Build the checklist JSON array

To build the array, we have 2 steps:

1. Build each element for all items that we get from the SharePoint list.
2. Combine all elements in an array.

Here’s what it looks like:

We’ll use an Apply to Each action that will check all elements from the SharePoint List. The formula is the following:

concat('{"id":"',items('For_Each_Element_in_the_Array')?['TaskID'],'","','title": "',items('For_Each_Element_in_the_Array')?['Title'],'","isChecked": false}')

It looks complex, but it’s a big concatenation of values. To do that, we’re using the “concat function.” As you can see in the formula, we’re fetching the items based on the column names in SharePoint. Also, we’re defining it as always “not checked” since adding an item already checked is not very useful, in my opinion.

To combine all, we’re using the “concat function” again and the join function.

concat('[',join(variables('ARRAY'),','),']')

You can find many more details on how the join function in my reference section, but in a nutshell, it fetches all elements in an array and combines them in a string with the separator you define. In our case, we want to use “,” to have the string that we need. So, the concatenate is adding “[“ and “]” in each side of the string. These characters indicate that we’re opening and closing an array of elements in JSON. 

In this section, we’ll do most of the work to add the checklist items dynamically. After this, we only need to add the string to the action, and we’re done.

Updates the task with the checklist items

Now that all is done, we only need to add the elements to the planning task. To do that, we can use the “Update task details” action. 

We need to provide a string with the JSON elements we previously built in the “Compose action.”

Final thoughts

The formulas may look a bit complex, but they become quite simple if you break them down in each element. All we’re trying to do is building the string that Power Automate and Microsoft Planner need to create the checklist items dynamically. As always, it’s all about strategy, so if you notice yourself constantly changing a Flow because some elements changed, think a bit deeper in how to optimize it so that you can speed up the whole process. 

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