Truthiness

When a non-boolean value is used in a boolean context (such as an if condition, while condition, or as an operand of and/or/not), it is evaluated according to the following rules.

Truthiness Table

Value	Truthy?
`null`	falsy
`false`	falsy
`0` / `0.0`	falsy
`""` (empty string)	falsy
`true`	truthy
Non-zero numbers	truthy
Non-empty strings	truthy
Arrays - including empty `[]`	truthy
Objects - including empty `{}`	truthy

Empty Arrays and Objects Are Truthy

Empty arrays and empty objects evaluate as truthy. This means an if check on a collection always passes, regardless of whether it contains any elements:

# INCORRECT - this block executes even when items is []
if Data.items then
    # This code runs for empty arrays!
end

# CORRECT - check length explicitly
if Length(Data.items) > 0 then
    # Only runs when array is non-empty
end

Logical Operators Return Operand Values

The and and or operators return one of their actual operand values, not necessarily true or false:

and returns the first falsy operand, or the last operand if all are truthy
or returns the first truthy operand, or the last operand if all are falsy

"hello" and "world"          # "world"
null and "skipped"            # null
null or "fallback"            # "fallback"
"first" or "second"           # "first"

The not operator always returns a boolean:

not null                      # true
not "hello"                   # false
not 0                         # true