Debugge in Visual Studio Code

I created a simple application in node.js

var app = require("express"); 
var express = express();

app.get("/", function(req, res){
res.send("Hello"); 
});
app.listen(3000);

and the launch.json file:

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "node",
            "request": "launch",
            "name": "Iniciar programa",
            "program": "${workspaceFolder}\index.js"
        }
    ]
}

When you start debugging with the Visual Studio Code it shows:

  

The 'program' attribute does not exist

Can someone help me with this error?