Blanket - more object oriented ?

gistfile1.js

/**
  * Module Depedencies
  */
var path = require('path');
/**
  * Export
  */
exports = module.exports = Blanket;

/**
  * CTO
  * @options
  * {
  *     files: {
  *         "filename" : @content
  *     }
  * }
  */
function Blanket(options){
    this.root = options.root;
    this.dest: options.dest;
    this.files: options.filesContent;
    this.onEachFileInstrumented: options.onEachFileInstrumented;
    this.onInstrumented = options.onInstrumented;
}
/**
  * Instrument file
  */
Blanket.prototype.instrumented = function(){
    var files = this.files,
        root = this.root,
        dest = this.dest;

    for(var file in files)
    {
        //TODO, move in private function
        var fileContent = files[file];
        var fileName  = file;
        var instrumentFileName = filename.replace(root, dest);
        var lines = inFile.split("\n");
        var instrumented = "";

        //TODO, we need to actually parse the js a bit,
        //or adding these lines can cause unprocessable js

        //set up namespace
        instrumented += "if (typeof _$blanket === 'undefined') { _$blanket = {}; }\n";
        //initialize file object
        instrumented += "_$blanket['"+inFileName+"']=[];\n";
        //initialize array values
        for (var j=0;j <lines.length; j++){
          instrumented += "_$blanket['"+inFileName+"']["+j+"]=0;\n";
        }
        for (var i=0; i<lines.length; i++){
          instrumented += "_$blanket['"+inFileName+"']["+i+"]++;\n";
          instrumented += lines[i]+"\n";
        }
        this.onEachFileInstrumented(instrumentFileName, instrumented);
    }
    this.onInstrumented();
};