node.js if/else statment error

I have this node code

    //change the variable to what the database file is
    var dataFile = "data.json";
    //set to port you want server hosted on
    var port = 8000;
    //End Of settings

    var fs = require('fs');
    var http = require('http'),
        url = require('url');

    if (fs.exists(require('path').resolve(__dirname, dataFile))) {
        data = JSON.parse(
            require('fs').readFileSync(
                require('path').resolve(
                    __dirname, 
                    dataFile),
                'utf8'));
                console.log("data setup!");

    } else {
        fs.writeFile(dataFile, "{}", function (err) {console.log("database         file has been created!");});
        console.log('Please restart ndb.js to get the database online.');
        console.log('you can quit with ctrl + c');
    }
    function writeSaveData() {
        fs.writeFile(dataFile, JSON.stringify(data), function (err) {
      if (err) throw err;
      console.log('Updated the file: ' + dataFile + " with new data");
      data = JSON.parse(
            require('fs').readFileSync(
                require('path').resolve(
                    __dirname, 
            dataFile),
                'utf8'));
                console.log("Completed re-sync of data");
    });
    }


    http.createServer(function (req, res) {
        query = url.parse(req.url,true).query;
        if(query.act) {
            if(query.act === 'store') {
                if(query.name && query.val){
                    eval('data.' + query.name + ' = "' + query.val + '"');
                    writeSaveData();
                    res.end("success!");
                } else {
                    res.end("{'error':'Error wrong parameters'}");
                }
            }
            if(query.act === 'read') {
                if(query.name) {
                    res.end(eval('data.' + query.name));
                } else {
                    res.end("{'error':'Error wrong parameters'}");
                }
            }
        } else {
        res.end("{'error':'Error wrong parameters'}");
        }
        //res.end(JSON.stringify(query));
    }).listen(port);
    console.log("Server running at http://localhost:" + port + '/');

what happens is that when i run this code it thinks that the if statement executes false and ends up resetting my file with data! I have no idea what is happening. I do have the data.json file with basic json in it so i don't know what is wrong!