Safely using console.* in browser

Question

I come from a Java background so my desire for proper unambiguous logging is strong. I prefer using the console to using some other gui widget however, in the browser I know that I can't always count on the console to exist or for it to have all the levels I might like. To remedy this I worked up the following console sanitizer and I was curious what drawbacks it might have.

function configureConsoleLog() {
    "use strict";
    var logMethods = [ 'trace', 'debug', 'log', 'info', 'warn', 'error' ], i;

    if (!window.console) {
        window.console = {log: function (args) {}}; //noop
    }

    for (i = 0; i < logMethods.length; i += 1) {
        if (!window.console[logMethods[i]]) {
            window.console[logMethods[i]] = window.console.log;
        }
    }
}

The idea is to find out if console exists and if it does try to find out which of the supported levels I need are available. The first level of fallback is to map unsupported methods to console.log. The second level is to create my own console variable and make a noop log function since I have nowhere to send the output. This approach leaves open the possibility of coming up with a different strategy if console doesn't exist but for now I'm content to ignore logging if there is no console.

As a side note I looked at several JS logging packages but all of them have the fatal drawback of obscuring original line numbers, usually by delegating to a console method which only reports the line number of the delegating statement.

Thoughts?

Answer 1

I don't see any problems with that. It's similar to this answer on SO.

Just a couple minor things:

• You don't need args in the empty log function

• You should make the entire function anonymous and execute it immediately (as it's being done in the answer I linked to); I don't think there's any usecase for calling it otherwise

• Don't forget var in front of the i variable, otherwise it becomes global