How to force an exception

I am using this library in my tests and so far it is great. However I am a unsure about how to use this to force an exception.

for example I am doing this

const {
  DynamoDBDocumentClient,
  UpdateCommand,
} = require('@aws-sdk/lib-dynamodb');
const {
  ConditionalCheckFailedException,
} = require('@aws-sdk/client-dynamodb');

const ddbMock = mockClient(DynamoDBDocumentClient);
ddbMock.on(UpdateCommand).rejects(ConditionalCheckFailedException);

However that does not throw the proper exception. Any ideas on what I need to do differently?

The code I am testing looks like this

if (error instanceof ConditionalCheckFailedException) {
      ...
}

For reference: https://aws.amazon.com/blogs/developer/service-error-handling-modular-aws-sdk-js/ https://docs.aws.amazon.com/aws-sdk-php/v3/api/class-Aws.DynamoDb.Exception.DynamoDbException.html#shape-conditionalcheckfailedexception

[m-radzikowski]

The ConditionalCheckFailedException constructor requires the message and $metadata properties, so the correct way to create it without any would be:

    ddbMock
        .on(UpdateCommand)
        .rejects(new ConditionalCheckFailedException({message: '', $metadata: {}}));

[automartin5000]

Actually, I was able to work around this with ddbMock.on(UpdateCommand).rejects(new ConditionalCheckFailedException('' as any));