CODEWITHSUNDEEP
javascriptnode.js
Sir
Sir

Reputation: 8277

NodeJS throw new TypeError

When i try to run my JS file i get this error:

http.js:783
    throw new TypeError('first argument must be a string or Buffer');

I was following this tutorial which didn't seem to mention the problem Tutorial Link

My JS file has:

var http = require('http'),
    fs = require('fs'),
    sanitize = require('validator').sanitize;

var app = http.createServer(function (request, response) {
    fs.readFile("client.html", 'utf-8', function (error, data) {
        response.writeHead(200, {'Content-Type': 'text/html'});
        response.write(data);
        response.end();
    });
}).listen(1337);

var io = require('socket.io').listen(app);

io.sockets.on('connection', function(socket) { 
    socket.on('message_to_server', function(data) { 
        var escaped_message = sanitize(data["message"]).escape();
        io.sockets.emit("message_to_client",{ message: escaped_message }); 
    });
});

I have Socket.io and validator installed in my node_modules folder. I'm quite new to this sort of stuff and looks like this tutorial wasn't a good starting choice, I can't seem to get it working.

Upvotes: 1

Views: 5391

Answers (1)

josh3736
josh3736

Reputation: 145102

You're not doing any error checking, and I'd bet that readFile is throwing an error. This means data is undefined, so when you try to response.write(data), the http module throws an error.

Always check the error parameter in your callback functions, and handle it appropriately.

fs.readFile("client.html", 'utf-8', function (error, data) {
    if (error) {
        response.writeHead(500, {'Content-Type': 'text/html'});
        response.write(error.toString());
    } else {
        response.writeHead(200, {'Content-Type': 'text/html'});
        response.write(data);
    }
    response.end();
});

Upvotes: 3

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