Examples of synchronous operational errors

[benjamingr]

I'd like to collect some examples of operational errors in Node that are synchronously thrown at the moment.

Please post examples you're aware of

Examples:

1. Out of memory
2. Parsing invalid JSON
3. Attempting to bind to a closed UDP socket.
4. Listening to an invalid port

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Out of memory

const arr = []; // example and case by trevnorris
  while (true)
    arr.push(new Buffer(0xfffffff).fill(0));  // alloc until OOM, throws synchronously

Parsing Invalid JSON

var j = JSON.parse("{'hello': 5}"); // throws synchronously

Attempting to bind to a closed UDP socket

From https://nodejs.org/api/dgram.html

If binding fails, an 'error' event is generated. In rare case (e.g. attempting to bind with a closed socket), an Error may be thrown.

Listening to an invalid port

https://github.com/nodejs/node/blob/master/lib/net.js#L1340

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Of course, every single *Sync method in the API throws synchronously, although in theory they could take callbacks and execute them with err synchronously. This includes calls to require for example.

[benjamingr]

Related discussion: #10

[petkaantonov]

I'd generalize that almost any error thrown in core can be operational depending on context. So just search for throw and there you go.

[benjamingr]

@petkaantonov care to share some examples?

[thefourtheye]

I found few such instances while working on nodejs/node#5251. I had to fix the tests as well because they were expecting errors synchronously.