AWS JavaScript SDK v3 with TypeScript 4.4.2 and @types/node 16.7.10 thrown error type

user_4690946 0
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I updated today (after a couple of months) my package.json file with the latest package versions, I think the ones impacting this error are the ones in the subject of the question.

Some error handling blocks as the following one

try {
  // ...
} catch(err) {
  console.log(err.message);
}

stopped working due to TypeScript error 2571: Object is of type 'unknown'.

Nice! I just had to apply following simple change:

try {
  // ...
} catch(err) {
  console.log(err instanceof Error ? err.message : JSON.stringify(err));
}

not only my code started to work once again, but I feel my code is more resilient as well.

The problem comes when I try to handle an error thrown from the AWS SDK v3.

import { CloudWatchLogs, ResourceNotFoundException } from "@aws-sdk/client-cloudwatch-logs";

const cwl = new CloudWatchLogs({ region: "us-east-2" });

try {
  const logGroupName = "...";
  const logStreamName = "...";
  const { events } = await cwl.getLogEvents({ logGroupName, logStreamName });

  // ...
} catch(err) {
  if(! (err instanceof ResourceNotFoundException)) console.log(err);
}

In the simplified (I'm not handling pagination) above code sample I simply want to ignore the ResourceNotFoundException, but the err instanceof ResourceNotFoundException check doesn't compile since ResourceNotFoundException is an interface rather than a class.

I found this answer which seems could help me.

The question is: should I write an instanceOf\w+Exception function (sorry for the regexp) for each AWS exception I need to handle, or is there a common and reusable way provided by AWS?

The main reason why I'm seeking for this is not that I'm lazy (and I am), but if I write my own instanceOf\w+Exception functions inspecting the AWS SDK source code, my functions may stop working if Amazon will change something in the SDK.

typescript node.js amazon-web-services javascript
2 Answers

I found this issue: I strongly suspect, at the moment, the answer is simply: no, there isn't.

Edit: the same issue was solved and now we can use the instanceof operator (I have not yet tested it).

user_46909460

Update 2022

AWS SDK v3 is now using instanceof and deprecating the typescript sdkerror

https://aws.amazon.com/blogs/developer/service-error-handling-modular-aws-sdk-js

import {
  InvalidSignatureException,
  ResourceNotFoundException,
  FooServiceException,
} from "@aws-sdk/client-foo";

Obviously replace foo by the client you are using

try {
  await client.send(someCommand);
} catch (e) {
  if (e instanceof InvalidSignatureException) {
    // Handle InvalidSignatureException
  } else if (e instanceof ResourceNotFoundException) {
    // Handle ResourceNotFoundException
  } else if (e instanceof FooServiceException) {
    // Handle all other server-side exceptions from Foo service
  } else {
    // Other errors
  }
}
user_38285810
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