Check out example codes for "send html file express". It will help you in understanding the concepts better.

Code Example 1

var express = require('express');
var app = express();
var path = require('path');

// viewed at http://localhost:8080
app.get('/', function(req, res) {
    res.sendFile(path.join(__dirname + '/index.html'));
});

app.listen(8080);

Code Example 2

res.sendFile(path.join(__dirname + '/index.html'));

Code Example 3

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

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