assertBoolean method Null safety

SassBoolean assertBoolean(
  1. [String? name]
)

Throws a SassScriptException if this isn't a boolean.

Note that generally, functions should use isTruthy rather than requiring a literal boolean.

If this came from a function argument, name is the argument name (without the $). It's used for error reporting.

Implementation

SassBoolean assertBoolean([String? name]) =>
    throw _exception("$this is not a boolean.", name);