如何用rethinkdb解决node js中的"is not a function"？

Question

TypeError: pollObject.addNewPolls is not a function
    at /home/imerit/iReNO/controllers/polls.js:23:16
    at Layer.handle [as handle_request] (/home/imerit/iReNO/node_modules/express/lib/router/layer.js:95:5)
    at next (/home/imerit/iReNO/node_modules/express/lib/router/route.js:131:13)
    at next (/home/imerit/iReNO/node_modules/express/lib/router/route.js:125:14)
    at Route.dispatch (/home/imerit/iReNO/node_modules/express/lib/router/route.js:112:3)
    at Layer.handle [as handle_request] (/home/imerit/iReNO/node_modules/express/lib/router/layer.js:95:5)
    at /home/imerit/iReNO/node_modules/express/lib/router/index.js:277:22
    at Function.process_params (/home/imerit/iReNO/node_modules/express/lib/router/index.js:330:12)
    at next (/home/imerit/iReNO/node_modules/express/lib/router/index.js:271:10)
    at Function.handle (/home/imerit/iReNO/node_modules/express/lib/router/index.js:176:3)
    at router (/home/imerit/iReNO/node_modules/express/lib/router/index.js:46:12)
    at Layer.handle [as handle_request] (/home/imerit/iReNO/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/home/imerit/iReNO/node_modules/express/lib/router/index.js:312:13)
    at /home/imerit/iReNO/node_modules/express/lib/router/index.js:280:7
    at Function.process_params (/home/imerit/iReNO/node_modules/express/lib/router/index.js:330:12)
    at next (/home/imerit/iReNO/node_modules/express/lib/router/index.js:271:10)

这是我在尝试调用 url 时遇到的错误。 polls.js代码如下。

"use strict";
var rethinkdb = require('rethinkdb');
var db = require('./db');
var async = require('async');

class polls {
  addNewPolls(pollData,callback) {
    async.waterfall([
      function(callback) {
        db.connectToDb(function(err,connection) {
          if(err) {
            return callback(true,"Error connecting to database");
          }
          callback(null,connection);
        });
      },
      function(connection,callback) {
        rethinkdb.table('poll').insert({
            "question" : pollData.question,
            "polls" : pollData.polls
        }).run(connection,function(err,result) {
          connection.close();
          if(err) {
            return callback(true,"Error happens while adding new polls");
          }
          callback(null,result);
        });
      }
    ],function(err,data) {
      callback(err === null ? false : true,data);
    });
  }
}

module.exports = polls;

我对节点 js 很陌生。有语法问题吗？我已经创建了控制器、模型和 app.js。我的控制器包含 home.js、index.js、polls.js，模型包含 db.js 和 polls.js。我正在尝试点击

http://localhost:3000/polls

我参考了This Link

Answer 1

你好像忘了实例化 class :

class A{ b(){console.log("sdsd");}}
A.b(); // undefined
(new A()).b(); // ok

将module.exports替换为：

module.exports = new polls();

Answer 2

你应该先新建数据库对象：

var dbObject = new db();
  dbObject.connectToDb(function(err,connection) {
  // your code here.
}

如何用rethinkdb解决node js中的"is not a function"？

how to solve "is not a function" in node js with rethink db?

node.js

rethinkdb