is ENOENT from fs.createReadStream uncatchable?

Question

I'm not able to catch ENOENT of fs.createReadStream(). Is this an asynchronous function , which throws exception in a different closure-chain ?

$ node -v v0.10.9 $ cat a.js fs = require('fs')  try  {   x = fs.createReadStream('foo'); } catch (e) {   console.log("Caught" ); }  $ node a.js  events.js:72         throw er; // Unhandled 'error' event               ^ Error: ENOENT, open 'foo' 

I am expecting 'Caught' to be printed rather than error stack !

Answer 1

fs.createReadStream is asynchronous with the event emitter style and does not throw exceptions (which only make sense for synchronous code). Instead it will emit an error event.

const fs = require('fs')  const stream = fs.createReadStream('foo'); stream.on('error', function (error) {console.log("Caught", error);}); stream.on('ready', function () {stream.read();});