我正在学习一个教程，我正在研究它的最后一部分.我试图通过一个'PUT'请求覆盖数据库的内容。

const express = require("express");
const bodyParser = require("body-parser");
const ejs = require("ejs");
const mongoose = require("mongoose");

const app = express();

app.set('view engine', 'ejs');

app.use(bodyParser.urlencoded({
    extended: true
}));
app.use(express.static("public"));

mongoose.connect("mongodb://localhost:27017/wikiDB", {useNewUrlParser: true});

const articleSchema = {
    title: String,
    content: String
};

const Article = mongoose.model("Article", articleSchema);

// Requests Targeting All Routes

app.route("/articles")

.get(function(req, res) {
    Article.find()
        .then((foundArticles) => {
            mongoose.connection.close();
            foundArticles.forEach(function(foundArticle) {
                // console.log(foundArticle);
                res.send(foundArticles);
            })
        })
        .catch(function(err) {
            console.log(err);
        })
})

.post(function(req, res) {
    const newArticle = new Article({
        title: req.body.title,
        content: req.body.content
    });

    newArticle.save()
        .then(function() {
            res.send("Successfully added a new article.");
        })
        .catch(function(err) {
            console.log(err);
        })
})

.delete(function(req, res) {
    Article.deleteMany()
        .then(() => {
            res.send("Successfully deleted the document.");
        })
        .catch(function(err) {
            console.log(err);
        })
});

// Requests Targeting Specific Routes

app.route("/articles/:articleTitle")
.get(function(req, res) {
    const title = req.params.articleTitle;
    Article.find({title})
        .then((foundArticle)  => {
            res.send(foundArticle);
        })
        .catch(function(err) {
            console.log(err);
        })
})

// It won't allow the contents of the database to be overwritten.
.put(function(req, res) {
    Article.replaceOne({ title: req.params.articleTitle },
        {
          title: req.body.title,
          content: req.body.content,
        })
        .then(() => {
            res.send("Successfully updated article.");
        })
        .catch(function(err) {
            console.log(err);
        })
})
app.listen(3000, function() {
    console.log("Server started on port 3000!");
});

数据库的内容采用以下格式：

{
    "_id" : ObjectId("6517a22854d8425f4e613d9e"),
    "title" : "REST",
    "content" : "REST is short for REpresentational State Transfer. It's an architectural style for designing APIs."
}

我在Postman中尝试了这个，没有错误。但问题是数据库的内容没有更新。由于没有显示错误，因此很难找出问题所在。