Edge Cases Quick Reference

Return Values on Empty or Missing Data

Function	Condition	Returns
`First(arr)`	Empty array	`null`
`Last(arr)`	Empty array	`null`
`IndexOf(arr, val)`	Not found	`-1`
`WhereByField(...)`	No matches	`[]` (empty array)
`FindByField(...)`	No match	`null`
`Find(arr, fn)`	No match	`null`
`AnyByField(...)`	Empty array	`false`
`AllByField(...)`	Empty array	`true` (vacuous truth)
`Any(arr, fn)`	Empty array	`false`
`All(arr, fn)`	Empty array	`true` (vacuous truth)
`Select(...)`	Empty array	`[]`
`SelectMany(...)`	Empty array	`[]`
`Project(...)`	Empty array	`[]`
`Omit(...)`	Empty array	`[]`
`Merge(arr)`	Empty array	`{}`
`Min(arr)`	No numbers	`null`
`Max(arr)`	No numbers	`null`
`Average(arr)`	No numbers	`null`
`Median(arr)`	No numbers	`null`
`Mode(arr)`	No numbers	`null`
`Sum(arr)`	No numbers	`0`
`ToNumber(s)`	Invalid string	`null`
`RegexMatch(...)`	No match	`null`
`RegexMatchAll(...)`	No matches	`[]`
`RegexMatchDetail(...)`	No match	`null`
`RandomChoice(arr)`	Empty array	`null`

Case Sensitivity

String comparisons (==, !=, <, >) are case-sensitive
Contains, StartsWith, EndsWith are case-sensitive
Query function comparisons are case-sensitive
Use ToLower() or ToUpper() for case-insensitive matching

Sort Order for Mixed Types

Sort groups elements by type, then sorts within each group:

null values (first)
Numbers (ascending)
Strings (lexicographic)
Booleans (false before true)

Split Preserves Empty Strings

The Split function preserves empty strings produced by adjacent or leading/trailing delimiters:

Split("a,,b", ",")        # ["a", "", "b"]
Split(",a,b,", ",")       # ["", "a", "b", ""]