Here's a kinda hacky workaround.  

As far as I can tell there isn't that much magic to lambdas for a single execution (The special sauce in the runtime environment, event handling, and auto scalability).  The Amplify CLI passes in the `event` object from `event.json` and calls the function defined as the handler.  You can do that in vanilla node js as well.

Create a file like `debug.js` - you can put it anywhere you want, but mine is in the `.vscode` directory

```js
const { handler } = require("../amplify/backend/function/sayHello/src")
const event = require("../amplify/backend/function/sayHello/src/event.json")

(async function(){

    // invoke
    const response = await handler(event)

    console.log(response)
})()
```

Then you can use a normal node js debug launch configuration like this:

```json
{
  "name": "Debug Function",
  "program": "${workspaceFolder}/.vscode/debug.js",
  "request": "launch",
  "skipFiles": ["<node_internals>/**"],
  "type": "pwa-node"
}
```

Something a little friendlier / out-of-the-box would be nice, but this at least allows step through debugging without too much extra work.

How can I debug Amplify JavaScript functions on VS Code on Windows 10?


This issue came up on github under [How to debug amplify function using visual studio code during invocation?][1], but it's closed and quite old.  For example, `amplify invoke function` is deprecated in favor of `amplify mock function`.

I've tried this `launch.config`:

```js
{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Launch Create Reort",
      "type": "node",
      "request": "launch",
      "program": "${env:APPDATA}/npm/node_modules/@aws-amplify/cli/bin/amplify",
      "args": [
        "mock",
        "function",
        "sayhello",
        "--event",
        "src/event.json",
        "--timeout",
        "0"
      ],
      "console": "integratedTerminal"
    }
  ]
}
```

Which will log the output, but doesn't hit any breakpoints inside the function being executed:

[![Example Output][2]][2]

### Setup steps:

1. Install amplify cli

   ```bash
   npm install -g @aws-amplify/cli
   ```

2. Initialize amplify.  Choose JavaScript with any framework.

   ```bash
   amplify init
   # Choose your default editor:                   Visual Studio Code
   # Choose the type of app that you're building:  javascript  
   # What javascript framework are you using:      none
   ```

3. Add function

   ```bash
   amplify add function SayHello
   # Choose the runtime that you want to use:            NodeJS
   # Choose the function template that you want to use:  Hello World
   ```


  [1]: https://github.com/aws-amplify/amplify-cli/issues/1158
  [2]: https://i.stack.imgur.com/wbX4w.png