@leizongmin nodejs新手,快速写出来的,求指导

var _ = require('lodash');
var mysql = require('mysql');
var Promise = require('bluebird');
/**
 * 构造函数
 * @param options 选项配置
 * @constructor
 */
function MyORM(options){
  this.connection = mysql.createConnection(options.connection);
  Promise.promisifyAll(this.connection);
}

MyORM.prototype.table = function(name){
   return new Query(this,name);
}

MyORM.prototype.execSQL = function(sql){
    console.log(sql);
    return this.connection.queryAsync(sql);
}
/**
 * 构造函数
 * @param orm MyORM对象
 * @param tableName 表名
 * @constructor
 */
function Query(orm,tableName){
    if(!tableName) throw new Error('tableName required');
    this._orm = orm;
    this._tableName = tableName;
}
Query.prototype.find = function(query){
  this._op = "SELECT";
  this._where = parseParamsObject(query);
  return this;
}
Query.prototype.select = function(select){
    this._select=select;
    return this;
}
Query.prototype.skip = function(skip){
  this._skip = skip;
  return this;
}
Query.prototype.limit = function(limit){
    this._limit = limit;
    return this;
}
Query.prototype.findOne = function(query){
    this._op = "SELECT_ONE";
    this._where = parseParamsObject(query);
    return this;
}
Query.prototype.delete = function(query){
    this._op = "DELETE";
    this._where = parseParamsObject(query);
    return this;
}
Query.prototype.update = function(query,update){
    this._op = "UPDATE";
    this._where = parseParamsObject(query);
    this._update = update;
    return this;
}
Query.prototype.save = function(save){
    this._op = "INSERT";
    this._save = save;
    return this;
}
/**
 * 生成SQL语句并且执行
 * @private
 */
Query.prototype._doQuery = function(){
  var sql,op = this._op;
  if(op === 'SELECT'){
      var select = this._select || '*';
      sql = 'SELECT '+select+' from '+this._tableName;
      if(this._where){
          sql += ' where ' + this._where;
      }
      var limit='';
      if(this._skip){
          limit += this._skip;
      }
      if(this._limit){
          if(limit) limit += ','
          limit += this._limit;
      }
      if(limit){
          sql += ' limit ' + limit;
      }
  }else if(op === 'UPDATE'){
      sql = 'UPDATE ' +this._tableName + ' SET '+ mysql.escape(this._update);
      if(this._where){
          sql += ' where ' + this._where;
      }
      if(this._limit){
          sql += ' limit '+this._limit;
      }
  }else if(op === 'DELETE'){
      sql = 'DELETE from ' +this._tableName;
      if(this._where){
          sql += ' where ' + this._where;
      }
      if(this._limit){
          sql += ' limit '+this._limit;
      }
  }else if(op === 'SELECT_ONE'){
      var select = this._select || '*';
      sql = 'SELECT '+select+' from '+this._tableName;
      if(this._where){
          sql += ' where ' + this._where;
      }
      sql += ' limit 1';
  }else if(op === 'INSERT'){
      sql = 'INSERT INTO ' +this._tableName + ' SET '+ mysql.escape(this._save);
  }
  var retVal = this._orm.execSQL(sql);
  if(op === 'SELECT_ONE'){
      retVal = retVal.then(function(rs){
          return rs[0];
      });
  }
  return retVal;
}

Query.prototype.then = function(){
  var pro = this._doQuery();
  return pro.then.apply(pro,arguments);
}

//简单的测试:

var orm = new MyORM({
    // mysql连接信息
    connection: {host: '127.0.0.1', port: 3306, user: 'root', password: '', database: 'test'},
});
orm.table('user').find({name:'高端人士',age:1,$or:{height:1,weight:2}})
    .skip(1).limit(10).select('name,age')
    .then(function(rs){
        console.log(rs);
    }).catch(function(e){
        console.error(e);
    })
	//sql == > SELECT name,age from user where (name='测试' AND age=1 AND (height=1 OR weight=2)) limit 1,10

/**
 * 简单的根据对象参数生成SQL的where条件,$and表示sql的and,$or表示sql的or
 * @param obj
 * @param parseValue
 */
function parseParamsObject(obj,parseValue){
    if(!parseValue){
        parseValue = function(key,value){
            //如需要处理大于小于等其他操作符的情况,可以自行修改
            return key + '=' + mysql.escape(value);
        }
    }
    return parse('$and',obj,parseValue)
}

function joinCriteria(arr,join){
    if(!arr || arr.length === 0){
        return;
    }
    return '('+arr.join(' '+join+' ')+')';
}

function parseChild(key,obj,join,parseValue){
    var ret = [];
    if(_.isArray(obj)){
        obj.forEach(function(val){
            if(_.isPlainObject(val)){
                var v = parseParamsObject(val,parseValue);
                if(v != null){
                    ret.push(v);
                }
            }
        });
    }else if(_.isPlainObject(obj)){
        Object.keys(obj).forEach(function(key){
            var val = obj[key];
            var v = parse(key,val,parseValue);
            if(v != null){
                ret.push(v);
            }
        });
    }
    return joinCriteria(ret,join);
}

function parse(key,val,parseValue){
    if(key === '$and'){
        return parseChild(key,val,'AND',parseValue);
    }
    if(key === '$or'){
        return parseChild(key,val,'OR',parseValue);
    }
    if(_.isPlainObject(val) && _.includes(Object.keys(val),'$or')){
        var vs = val['$or'];
        var temp = [];
        if(_.isArray(vs)){
            vs.forEach(function(ele){
                var v = parseValue(key,ele);
                if(v != null){
                    temp.push(v);
                }
            });
        }
        return joinCriteria(temp,'OR');
    }
    return parseValue(key,val);
}