code: function (customProperty, declaration) {
    customProperty.declarations.forEach(function (customDeclaration) {
      // No need to copy value here as replace will copy value
      var value = customDeclaration.value;
  
      // Replace parameter variables with user given values
      customDeclaration.variables.forEach(function (variable) {
        value = value.replace(customProperty.parameters[variable],
          declaration.values[variable]);
      });
  
      // Using cloneBefore to insert declaration provides sourcemap support
      declaration.cloneBefore({
        prop: customDeclaration.property,
        value: value
      });
    });
  
    declaration.remove();
  }
docs: Applies the custom property to the given declaration