node JS client vs server

Question

I am a PHP developer and have recently made some use of node JS with express.

One thing i am confused about is how you tell your express server if a javascript file should be executed on the server or sent to the browser to be executed on the client side.

In PHP this is not a problem because each filetype (php, pearl, jpg, js) has a dedicated location (server or client) where it runs. The same is true of HTTP apps programmed other languages such as Java and C#

consider this sample code

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

app.get('/some_page', function(req, res) { res.send('hello world'); });

app.listen(3000);

There is no JS involved so 'hello world' is sent to the browser and is rendered by the browser.

But what if the code was

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

app.get('/', function(req, res){ res.send('console.log('hello world')'); });

app.listen(3000);

This time we have the JS function console.log() So how does node.js know if if should run this code or send it to the browser.

It seems you need to learn basics of node.js prior jumping to express.js — Zeeshan Hassan Memon

Yinkaking Yinkaking · Accepted Answer · 2016-03-07T11:27:48

this is all whithin the app.get('/', function(req, res){ and } tags

res.send('console.log("hello world!")')

will print console.log("hello world!") on the clients page

res.send('<html><body><script>console.log("hello world!");</script></body></html>')

will print hello world! in the console of the client

 res.send('hello world!');
 console.log("hello world!");

will print hello world! on the page of the client and on the servers console.

so basicly all you send to the client will be done client-side and code that you dont send to the client will be done server-side

EDIT

like Ankur Rana said you can also send Html files

res.sendFile('index.html');

and in the same directory as this file we have a file named index.html:

<html>
<body>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
    <div id="myId">console.log("hello world!")</div>
    <script>
        //regular js here
     $("#myId").html("Hello World!");
    </script>
</body>
</html>

node JS client vs server

3 Answers