tracer.js

/* tracer.js - A tracer utility in 2kb
 *
 * @author Angus Croll
 * http://javascriptweblog.wordpress.com/2010/06/01/a-tracer-utility-in-2kb/
 */

String.prototype.times = function(count){
  return count < 1 ? '' : new Array(count + 1).join(this);
}

var tracer = {
  nativeCodeEx: /\[native code\]/,
  traceEx: /function traceOn\(/,
  indentCount: -4,
  tracing: [],

  traceMe: function(func, methodName){
    function traceOn(){
      var startTime = +new Date;
      var indentString = ' '.times(tracer.indentCount += 4);
      console.info(indentString + methodName + '(' + Array().slice.call(arguments).join(', ') + ')');
      var result = func.apply(this, arguments);
      console.info(indentString + methodName, '-> ', result, '(', new Date - startTime, 'ms', ')');
      tracer.indentCount -= 4;
      return result;
    }
    traceOn.traceOff = func;
      for (var prop in func){
      traceOn[prop] = func[prop];
    }
    console.log('tracing ' + methodName);
    return traceOn;
  },

  traceAll: function(root, recurse){
    if ((root == window) || !((typeof root == 'object') || (typeof root == 'function'))){ return; }
    for (var key in root){
      if ((root.hasOwnProperty(key)) && (root[key] != root)){
        var thisObj = root[key];
        if (this.traceEx.test(thisObj)) continue;
        if (typeof thisObj == 'function'){
          if ((this != root) && !this.nativeCodeEx.test(thisObj)){
            root[key] = this.traceMe(root[key], key);
            this.tracing.push({ obj: root, methodName: key });
          }
        }
        recurse && this.traceAll(thisObj, true);
      }
    }
  },

  untraceAll: function(){
    for (var i = 0; i < this.tracing.length; ++i){
      var thisTracing = this.tracing[i];
      thisTracing.obj[thisTracing.methodName] = thisTracing.obj[thisTracing.methodName].traceOff;
    }
    console.log('tracing disabled');
    tracer.tracing = [];
  }
}