[This is preliminary documentation and subject to change]
You attempted to create an expression using the ternary conditional operator, but did not include the colon between the second and third operands. The ternary (three operands) conditional operator requires a colon between the second (true) and third (false) operands.
To correct this error
Conditional (Ternary) Operator (?:) | JScript Operators | JScript Language Reference