node.js TypeError: path must be absolute or specify root to res.sendFile [failed to parse JSON]

Question

[add] So my next problem is that when i try adding a new dependence (npm install --save socket.io). The JSON file is also valid. I get this error: Failed to parse json

Answer 1

It will redirects to index.html on localhost:8080 call.

app.get('/',function(req,res){
    res.sendFile('index.html', { root: __dirname });
});