Error Handling

When working with DynamoQL, 3 type of error may be thrown:

• DynamoQL related error
• aws-sdk v3 related error
• runtime error

All DynamoQL related error are instances of DynamoQLException.
Here's hierarchy tree of all DynamoQL exceptions:

• DynamoQLException
  • DynamoQLForbiddenOperationException
  • DynamoQLValidatorException
    • DynamoQLInvalidTypeException
    • DynamoQLMissingKeyException
    • DynamoQLInvalidEnumException
    • DynamoQLInvalidMinMaxException
    • DynamoQLCustomValidatorException

DynamoQLForbiddenOperationException is thrown during update request when

• Removing a required attribute
• Setting unknown attribute
• Increasing / Decreasing an enum
• using invalid $.. expression

Both DynamoQLForbiddenOperationException and DynamoQLValidatorException includes TableName.

DynamoQLValidatorException includes details, an object which provides attribute paths and error messages.

import { DynamoQLException, DynamoQLValidatorException } from "dynamoql";
import { ProvisionedThroughputExceededException } from "@aws-sdk/client-dynamodb";

// pseudo Express route middleware
const createUser = (req, res, next) => {
  try {
    await User.put(req.body);
  } catch (error) {
    if (error instanceof DynamoQLException) {
      if (error instanceof DynamoQLValidatorException) {
        return res.json(error);
      }
      // handle other error
    } else if (error instanceof ProvisionedThroughputExceededException) {
      // handle retry
    } else {
      next(error);
    }
  }
};

info

When DynamoQLValidatorException is JSON.stringifed it returns only details

tip

When overwriting an error message you can use getTypeFromKeyPath to get error related attribute Schema.

try {
  await User.put(req.body);
} catch (error) {
  if (error instanceof DynamoQLInvalidEnumException) {
    const frontendErrorMessages = {};

    Object.entries(error).forEach(([key, message]) => {
      const schema = userSchema.getTypeFromKeyPath(key);

      frontendErrorMessages[key] = `Անվավեր մուտքագրում: Դուք կարող եք օգտագործել միայն ${schema.enum.join(", ")}`;
    });

    return frontendErrorMessages;
  }
}