DataWeave 2.2 is compatible and bundled with Mule 4.2. Standard Support for Mule 4.2 ended on May 2, 2021, and this version of Mule will reach its End of Life on May 2, 2023, when Extended Support ends.

Deployments of new applications to CloudHub that use this version of Mule are no longer allowed. Only in-place updates to applications are permitted.

MuleSoft recommends that you upgrade to the latest version of Mule 4 that is in Standard Support so that your applications run with the latest fixes and security enhancements.

failIf(T, (value: T) -> Boolean, String): T

Produces an error with the specified message if the expression in the evaluator returns true, otherwise returns the value.


Name Description


The value to return only if the evaluator expression is false.


Expression that returns true or false.


This example produces a runtime error (instead of a SUCCESS message) because the expression isEmpty(result) is true. It is true because an empty object is passed through variable result.


%dw 2.0
import failIf from dw::Runtime
var result = {}
output application/json
{ "result" : "SUCCESS" failIf (isEmpty(result)) }


ERROR 2018-07-29 11:56:39,988 ...
Message               : "Failed

Was this article helpful?

💙 Thanks for your feedback!

Edit on GitHub
Submit your feedback!
Share your thoughts to help us build the best documentation experience for you!
Take our latest survey!