Question

I’ve noticed Node.js crashes on Type Errors even if your catching uncaught exceptions, here’s some example code:

var http = require('http');

process.on('uncaughtException', function (err) {
  console.log(err.stack);
});

var test = [];

// This causes the error because test[0] is undefined
console.log(test[0].toLowerCase());

http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
}).listen(1337, "127.0.0.1");

Is there any way to catch the error and keep node.js running.

Update: I should mention that the uncaughtException handler is firing in this case but it still crashes after it.

Answer 1

The exception itself is not closing your program, node is stopping because there is nothing left in the event queue.

An exception still stops execution of the current function/context, so it is never getting to your http.createServer. If you move your error to just beyond the http command, it will work as expected. 🙂