http://mongodb.github.io/node-mongodb-native/3.1/quick-start/quick-start/

一、安装使用mongodb库

1. 安装
   npm install mongodb --save
2. 引入 mongodb 下的MongoClient
   const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
3. 定义数据库连接的地址以及配置数据库名称

// Connection URL
const url = 'mongodb://localhost:27017';

// Database Name
const dbName = 'myproject';

4. nodejs连接数据库

// Create a new MongoClient
const client = new MongoClient(url);
// Use connect method to connect to the Server
client.connect(function(err) {
  assert.equal(null, err);//如果没有报错
  console.log("Connected successfully to server");

  const db = client.db(dbName);

  client.close();
});

5. 操作

const collection = db.collection('documents');
  // Insert some documents
  collection.insertMany([
    {a : 1}, {a : 2}, {a : 3}
  ], function(err, result) {
    assert.equal(err, null);
    assert.equal(3, result.result.n);
    assert.equal(3, result.ops.length);
    console.log("Inserted 3 documents into the collection");
    callback(result);
  });