使用$ positioning operator + embedded document + mongodb + nodejs编写复杂的搜索查询

Question

mongoose schema：

const userSchema = mongoose.Schema({
  name: {
    type: String,
    required: true
  },
  industry: {
    type: String,
    required: true
  },
  members: [
    {
      name: {
        type: String,
        required: true
      },
      contact: {
        email: {
          type: String,
          required: true
        },
        phone: {
          type: String
        }
      },
      role: {
        type: String,
        required: true
      }
    }
  ]
});

需要使用查询的电子邮件检索成员。 mongo shell命令：

db.users.find({"members.contact.email": "johndoe@acmecorp.com"}, {"members.$": 1});

完美地获取结果：

{
    "_id" : ObjectId("5b17cde35b5da82e2e8bb013"),
    "members" : [ 
        {
            "name" : "John Doe"
            "contact" : {
                "email" : "johndoe@acmecorp.com"
            },
            "_id" : ObjectId("5b18d38c869d6c409e17292f"),
            "role" : "Network Engineer"
        }
    ]
}

尝试在node.js应用中实现此查询时，用户＆＃39;模型函数定义为：

// Get member by email
module.exports.getMemberByEmail = function(email, callback) {
  var query = {{"members.contact.email": email}, {"members.$": 1}};
  User.find(query, callback);
};

但是语法错误：

var query = {{"members.contact.email": email}, {"members.$": 1}};
           ^

SyntaxError: Unexpected token {
    at createScript (vm.js:74:10)
    at Object.runInThisContext (vm.js:116:10)
    at Module._compile (module.js:533:28)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
    at Function.Module._load (module.js:458:3)
    at Module.require (module.js:513:17)
    at require (internal/module.js:11:18)
    at Object.<anonymous> (/home/demoapp/routes/users.js:5:14)
    at Module._compile (module.js:569:30)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
    at Function.Module._load (module.js:458:3)
    at Module.require (module.js:513:17)

对MEAN堆栈有点天真。任何有关正确语法的帮助都表示赞赏。

环境：

• node v8.0.0
• mongoose v4.10.4
• mongoDB v3.4.10