node.js - When router.get("conten1") is used twice, an error is reported. please help

Question

image description

Result1 directly reports an error, please help

Answer 1

Why

1. When the first get route is parsed successfully, the server will render content1 directly without waiting for the second one. This is why there is a next in the parameter.

2. In express, the order of routes is next to each other. If you do not use next, then only the callback method in the first get() will be triggered by default.

Solution

Synchronize query and finally render together

I am also a novice, I wrote some code for you to explain the logic problem

let data = {};
router.get('/', function (req, res, next) {
    data = {};
    //模拟DB查询回调
    setTimeout(function () {
        data.user = {id: 1, username: 'zhaojunlike'};
        //传递到下面
        next();
    }, 1000);

});
router.get('/', function (req, res, next) {
    console.log(data);
    //模拟第二次查询并且输出Render
    setTimeout(function () {
        data.content = {email: 'zhaojunlike@gmail.com'};
        res.render('index', {title: 'Express', data: data});
    }, 1000);

});