assertParam method
Throws ApiError if param
does not exist as route parameter in this
pattern.
If isOptional
is non-null, it is also asserted, that the route
parameter is optional or not.
Implementation
void assertParam(String param, {bool? isOptional}) {
if (!containsParam(param) || (isOptional != isOptionalParam(param))) {
final buffer = StringBuffer('RoutePattern requires ');
if (isOptional != null) {
if (!isOptional) {
buffer.write('non-');
}
buffer.write('optional');
}
buffer.write(' parameter "$param".');
throw ApiError(buffer.toString());
}
}