UberLogger

gistfile1.txt

(function() {
  if(typeof(console) == 'undefined') {
    (function() {
      /* Shim for window.console */
      var methods = ['log', 'info', 'warn', 'error'];
      window.console = {};
      for(var i = 0; i < methods.length; i++){
        window.console[ methods[i] ] = function() {};
      }
    })();
    
    /* Load up firebug lite */
    if(/debug/i.test(window.location.hash)) {
      var script = document.createElement('script');
      script.setAttribute("type", "text/javascript");
      script.setAttribute("src", "https://getfirebug.com/firebug-lite.js#startOpened");
      (document.getElementsByTagName("head")[0] || document.documentElement).appendChild(script);
    };
  };

  var Logger = {
    DEBUG: 0,
    INFO:  1,
    WARN:  2,
    ERROR: 3,
    level: 3  // default to WARN
    ,_log: function(level) {
      if(level >= this.level) {
        /* console.log/info/warn/error doesn't have apply method. */
        Function.prototype.apply.call(
          console[ level == 0 ? 'log' :
                   level == 1 ? 'info' :
                   level == 2 ? 'warn' :
                   level == 3 ? 'error' : 
                   'debug'],
          window.console, Array.prototype.slice.call(arguments, 1)[0] );
      }
      return;
    }
    ,log: function()    { this._log.call(this, this.level, arguments); }
    ,debug: function()  { this._log.call(this, this.DEBUG, this._addLogLevel('DEBUG', arguments)); } 
    ,info: function()   { this._log.call(this, this.INFO,  this._addLogLevel('INFO ',  arguments)); }
    ,warn: function()   { this._log.call(this, this.WARN,  this._addLogLevel('WARN ',  arguments)); }
    ,error: function()  { this._log.call(this, this.ERROR, this._addLogLevel('ERROR', arguments)); }
    ,_addLogLevel: function(level, msg) {
      typeof(msg[0]) == 'object' ?
        Array.prototype.splice.call(msg, 0, 0, level + " %o") :
        msg[0] = level + " " + msg[0];
      return msg;
    }
  };

  window.logger = Logger;
})();