Exception classes

OCCT throws subclasses of Standard_Failure. Native WASM exception handling surfaces them as WebAssembly.Exception values and the initialized runtime decodes their C++ type and message.

import oc from 'libcascade';

try {
  riskyOcctCall();
} catch (error: unknown) {
  if (error instanceof WebAssembly.Exception) {
    const [type, message] = oc.getExceptionMessage(error);
    console.error(`${type}: ${message}`);
  } else {
    throw error;
  }
}

WebAssembly.Exception.message does not contain the C++ failure text. Use the helper while the exception belongs to the current runtime. The related incrementExceptionRefcount and decrementExceptionRefcount instance helpers exist only for code that retains an exception beyond its catch scope.

Common hierarchy

Standard_Failure
├── Standard_OutOfRange
├── Standard_NullObject
├── Standard_NoSuchObject
├── Standard_TypeMismatch
├── Standard_DomainError
├── Standard_DivideByZero
└── Standard_ProgramError
    └── Standard_NotImplemented

See Debugging WASM exceptions for failure patterns and debug builds.