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

This can be resolved in another way:

app.get("/", function(req, res){

    res.send(`${process.env.PWD}/index.html`)

});

process.env.PWD will prepend the working directory when the process was started.