Question

我一直收到此错误Cannot call method 'insert' of undefined，我无法理解原因。我正在按照教程进行操作，虽然我们的代码是相同的，但它不适合我。这是代码。

var mongo = require("mongodb");
var host = "127.0.0.1";
var port = mongo.Connection.DEFAULT_PORT;
var db = new mongo.Db("nodejs-introduction", new mongo.Server(host, port, {}));
db.open(function(error) {

  console.log("We are connected " + host + ":" + port);

  db.collection("user", function(error, collection) {
    console.log("We have the collection");

    collection.insert({
        id: "1",
        name: "John Smith",
        twitter: "johns",
    }, function() {
      console.log("Successfully inserted John");
    });

    collection.insert({
        id: "2",
        name: "Eric Cartman",
        twitter: "cartman",
    }, function() {
      console.log("Successfully inserted Eric");
    });
  });
});

Answer 1

您从未定义变量collection，因此未定义。尝试console.log(collection);检查这是否属实。我很惊讶本教程适用于某人。

要解决问题，只需使用以下代码定义您的收藏：var collection = db.collection('user');

Answer 2

尝试使用它并查看它是否有效：

var collection = db.get('user');

collection.insert({
    id: "1",
    name: "John Smith",
    twitter: "johns",
}, function() {
    console.log("Successfully inserted John");
});

无法调用undefined的方法'insert'

2 个答案: