KB-1182 "Expression evaluation error at function 'reduce' [line #]" error thrown when using reduce() function with nested lists

Symptoms

When using the reduce() function and the "function" parameter is set to a function whose result is an array (i.e. apply()) the following error is observed:

Expression evaluation error at function ‘reduce’ [line #]: 

Cause

This issue has been reported to the Appian product team. The reference number for this issue is AN-70271.

Action

Do not use looping functions within a reduce() function.

Affected Versions

This article applies to all versions of Appian.