问将回调转换为thunk

EN

 var _project = yield parse(this);
var userdetails = this.req.user;
var that = this ;
//=============================================================
//FInd a user , check the project name exists under the user, if not then create one
//=============================================================
User.findOne({ '_id': userdetails._id }, function (err, user) {
    if (err) {
        this.body = "please login again , your session seems to have expired"
    } console.log(user.projects.owner.indexOf(_project.name));
    if(user.projects.owner.indexOf(_project.name) == -1) { //This means the project is not yet created
        var temp_project = new Project(_project);
            temp_project.save(function save() {
            if(err) {
                that.body = "Project coudn't be saved, Please try again sometime later";
            } else {
                user.projects.owner.push(_project.name);
                user.save(function save() {
                if (err) {
                    that.body = "This error is highly unlikely, yet if you see this .Please report this issue";
                }
                });
                that.body = temp_project;
            }
            });
    }
     if(user.projects.owner.indexOf(_project.name) >= 0) { //THis means the project exists
        that.body = "You have already created a project with same name, please use a different name";
         console.log("you reached till here");
    }
});

function userfindONE(err, user) {
    if (err) {
        return "please login again , your session seems to have expired"
    } 
    if(user.projects.owner.indexOf(tproject.name) == -1) { //This means the project is not yet created
        var temp_project = new Project(tproject);
            temp_project.save(function save() {
            if(err) {
                return "Project coudn't be saved, Please try again sometime later";
            } else {
                user.projects.owner.push(tproject.name);
                user.save(function save() {
                if (err) {
                    return "This error is highly unlikely, yet if you see this .Please report this issue";
                }
                });
                return temp_project;
            }
            });
    }
     if(user.projects.owner.indexOf(tproject.name) >= 0) { //THis means the project exists
        return "You have already created a project with same name, please use a different name";
    } else return "nothing is matching";
}

function userfindone(userdetails) {
return function(cb) {
    User.findOne({ '_id': userdetails._id }, cb);
  };
}
 var userdetails = this.req.user;
var tproject = yield parse(this);

this.body = yield userfindone(userdetails)(userfindONE) ;