Incorrect ReturnType of `DurableOrchestrationClient.getStatus`

[christianemmert]

Describe the bug DurableOrchestrationClient interface states that getStatus() returns Promise<DurableOrchestrationStatus>. This is correct for instances that exist and weren't purged. But for purged instances getStatus() returns an empty string. This is highly unexpected and should be fixed.

Investigative information

• Durable Functions extension version: 4.0.5030
• durable-functions npm module version: 1.5.4
• Language (JavaScript/TypeScript) and version: 4.8.4 (Typescript)
• Node.js version: 16.15.1

To Reproduce Steps to reproduce the behavior:

const client = getClient(context);
const instanceId = await client.startNew("MY_ORCHESTRATOR");

await client.getStatus(instanceId) // -> returns DurableOrchestrationStatus object

await client.purgeInstanceHistory(instanceId)
await client.getStatus(instanceId) // -> returns ""

Expected behavior Interface of DurableOrchestrationClient.getStatus() represents the actual ReturnType of the method.

[davidmrdavid]

FYI @hossam-nasr

[christianemmert]

The problem is in https://github.com/Azure/azure-functions-durable-js/blob/2857fc579ba61b91673e5a4b259bf9ce2386bd1c/src/durableorchestrationclient.ts#L229. When no instance is found the client will return a status code of 404 as such response.data won't have the shape of DurableOrchestrationClient but rather an empty string.

[hossam-nasr]

Fixed by #512