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Getting errors with null fields

  • Άρθρο

This article provides information to help you handle flow runtime errors and unexpected behaviors related to null fields.

Applies to:   Power Automate
Original KB number:   4535432

Symptoms

When you create a flow in Power Automate, you might experience the following issues:

  • Unexpected behaviors occur when performing an action with a null field.

  • Runtime errors occur if you don't handle null fields correctly. For example:

    InvalidTemplate. Unable to process template language expressions. The provided value is of type 'Null'.

    Screenshot of the invalid template runtime error.

Cause

  • If an action receives a null field as input when it expects a different value, it can result in incorrect behavior.
  • If an expression expects its parameter to be a string, an object, or an array but instead receives a null response, it can result in a runtime error.

Resolution 1: Add a condition check

To check for a null response, you can add a condition to the flow by following these steps. Then you can appropriate action to handle the condition.

  1. In the Power Automate flow, add a new Condition action.

  2. Choose the dynamic content output that you want to check. For example, User email.

  3. Set the operation to is not equal to.

    Screenshot of the operation setting.

  4. In the value field, add the expression value as null.

    Screenshot of the value setting of the condition.

    Screenshot of the null expression value set up for the condition.

Resolution 2: Use the coalesce function

You can also use the coalesce function to provide default values when a value is null. For example, using coalesce(trigger().outputs, '') will default to an empty string when trigger().outputs is null.

Screenshot to use the coalesce function to provide the default values when a value is null.

Note

If you still get a runtime error after using the coalesce function, it might be caused by referencing null properties in an object. You can use the question mark operator (?) to handle null outputs from a trigger. For example: @coalesce(trigger().outputs?.body?.<someProperty>, '<property-default-value>').

For more information, see Coalesce and Operators.