assertMixin method

SassMixin assertMixin(
  1. [String? name]
)

Throws a SassScriptException if this isn't a mixin reference.

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

Implementation

SassMixin assertMixin([String? name]) =>
    throw SassScriptException("$this is not a mixin reference.", name);