Hi rdp ,
Thank you for reaching out Microsoft Q&A forum.
I ran into the same problem as you did. So replicated the learn lab using Create your first durable function in Azure using JavaScript | Microsoft Learn as a guide in VS Code. When I attempted to debug, I received Worker was unable to load function OrchFunction: 'df.orchestrator is not a function'
error message stating that the OrchFunction was not a function, even though everything was created successfully. I downgraded the durable-functions package to 2.1.4 it successfully ran locally. After that, I went back to the console in the sandbox and ran npm install durable-fuctions@2.1.4
and reran the HttpStart function URL. Low and behold, it successfully ran. Since this is node we're dealing, it could be an issue between the 3.1.0 and Node 18. I'll share this feedback with the team but for now, I suggest using 2.1.4 or trying using a different version of Node.
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Thank you.