sort member functions should accept compare and compareNoCase functions as comparator callbacks| View in Tracker
See: http://blog.adamcameron.me/2017/04/cfml-lucee-13-v-4-14-v-6-coldfusion-we.html This should work: arrayToSort = ["d","C","b","A"]; arrayToSort.sort(compareNoCase); It doesn't do anything (not even error). This should also work: listToSort = "d,C,b,A"; sortedList = listToSort.listSort(compareNoCase); This one just errors: You have specified invalid sorting inputs. It could be a UDF functions or type. That's not correct. A BIF should also work. More details & test cases in the blog article.