I used koa scaffold for the project, and koa router was used for routing mongodb To connect to MongoDB

Example

First, set a public method mongo.js. Here is only one query method:

var MongoClient = require('mongodb').MongoClient;
var url = 'mongodb://localhost:27017/';

module.exports = {
    /**
     * @param option
     * {
     *    tableName <String> Collection name
     *    obj <object> Query data
     * }
     */
    find:function (option={}) {
        return new Promise(function (resolve,reject) {
            MongoClient.connect(url, function(err, db) {
                if (err) throw err;
                var dbase = db.db("blog"); //Database name
                dbase.collection(option.tableName).find(option.obj).toArray(function(err, result) { // Return all data in the collection
                    if (err) throw err;
                    db.close();
                    resolve(result);
                });
            });
        })
    }
}

Then route / index.js

const router = require('koa-router')();
const mongodb = require('./common/mongo');

router.get('/list', async (ctx, next) => {
    ctx.state.appName = 'Managing blogs';
    ctx.state.data ={
        tpl:"list"
    }
    ctx.state.data.list =await mongodb.find({
        tableName:'list',
        obj:{}
    });
    await ctx.render('index/index'); //Render Page
});

Next is rendering page index.ejs. I use the EJS template engine here, as follows:

<% if(locals.data&&locals.data.list){%>
    <% for(var i = 0; i<locals.data.list.length;i++){%>
        <%= locals.data.list[i].categories%>
    <%}%>
<%}%>

The database structure is as follows:

Conclusion:

Let's simply say that await follows a Promise. It must be used together with async. When Promise resolve s(), the value will be assigned again. Because the read data is asynchronous, it is not only ctx.render('index/index '); it needs await,mongo.find and await