According to the ActionScript language reference, the star type:
Specifies that a property is untyped. Use of the asterisk symbol for a type annotation is equivalent to using no type annotation. Expressions
that read from untyped properties are considered untyped expressions. Use of untyped expressions or properties is recommended in the following
circumstances:
- When you want to defer type checking to runtime. You can use an untyped property or expression to circumvent compile-time type checking in
strict mode. Note, however, that runtime type checking of assignment statements occurs whether you use strict mode or not.
- When you want to store the value undefined in a property. Unlike previous versions of ActionScript, the value undefined is not a member of
the Object data type. You must use an untyped property to store the value undefined.
But deferring type checking to runtime can highly impact the robustness of the application because the compiler is unable to assist the
developer.
Noncompliant code example
var obj:*; // Noncompliant
var foo:* = new Something(); // Noncompliant
Compliant solution
var obj:Something;
var foo:Something = new Something();
