Question

I was reading about console.log() somewhere on Stackoverflow earlier today, and I remember reading that it causes IE to bug out. The user had said that all instances of it should be removed from the code before deployment or a javascript library could be used to omit it in IE.

My question is regarding this second option, how would one write such a library? Would it just be something that’s run onload that affects how the js is parsed from then forward? Like something that says if browser == IE, omit all instances of console.log()… or would it be an extension to the console.log() method that makes it self-aware of what browser it’s being called in? I’m somewhat familiar with extending jQuery functions but have never seen this done with raw js. I’m interested in this because I feel like it would be a good way to achieve browser cross-compatiblity just in general, this isn’t about console.log() specifically.

Answer 1

There are a few different ways to go about testing for global properties that may or may not exist. You should try to be as defensive as possible, e.g.

var global = this;

if (!('console' in global)) {
  global.console = {};
}

if (!('log' in global.console)) {
  global.console.log = /* whatever */;
}

The in tests could perhaps use typeof instead. The idea is to not use an identifier that may not exist. Perhaps a little saner is:

// If console exists, declaring it will not hurt
// If it didn't exist, it does now
var console;

if (typeof console == 'undefined') {
  console = {};
}

if (typeof console.log == 'undefined') {
     console.log = /* whatever */;
}