[英]How to display comments from a JSON server using javascript and HTML?
我正在制作这个网站项目,人们可以在其中发表评论,网页将动态显示评论而无需重新加载页面。 我的评论以Allcomments=[ { username: 'username', info: 'title', commentinfo: 'commentinfo ' }]
格式存储在我的服务器中的数组中。 当我尝试运行我的代码Uncaught (in promise) ReferenceError: res is not defined at main.js:53 at async loadComments (main.js:50)
时,我目前收到此错误,因此未显示注释。 我也对如何实现 function 感到困惑,以便它在不需要重新加载页面的情况下更新新评论。 任何帮助或提示将不胜感激:这是我的代码: index.html
<html>
<body>
<main>
<div class="container">
<hr>
<h1>comments !</h1>
<hr>
<div class="row" id='commentsSection'></div>
</div>
</div>
</main>
<script src='client.js'></script>
</body>
</html>
客户端.js
async function GetComments () {
let info = {
method: 'GET',
headers: {
'Content-Type': 'application/json'
},
};
await fetch('http://127.0.0.1:8090/comments', info)
.then((res) => { return res.json(); })
.then(data => {
document.getElementById('commentsSection').innerHTML;
}).then(() => {
const comments = JSON.stringify(res);
for (let comment of comments) {
const y = `
<div class="col-4">
<div class="card-body">
<h5 class= "card-title">${comment.name}</h5>
<h6 class="card-subtitle mb-2 text-muted">${comment.info}</h6>
<div>comment: ${comment.comment}</div>
<hr>
</div>
</div>
`;
document.getElementById('commentsSection').innerHTML =
document.getElementById('commentsSection').innerHTML + y;
}
});
}
GetComments();
服务器.js
const app = express();
const port = 8090;
const express = require('express')
const bodyParser = require('body-parser');
const cors = require('cors');
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());
let Allcomments=[];
app.get('/comments', (req, res) => {
res.json(Allcomments);
});
您在.then
块中使用 res ,但您没有从较早的then
块中传递它:
.then((res) => { return res.json(); }) // res is defined within this block only
.then(data => {
document.getElementById('commentsSection').innerHTML;
.then(() => {
const comments = JSON.stringify(res); // <- ReferenceError: res is not defined
这应该解决它:
await fetch('http://127.0.0.1:8090/comment', info)
// extract data from response body:
.then((response) => { return response.json(); })
// response body is comments array
.then(comments => {
for (let comment of comments) {
const y = `
<div class="col-4">
<div class="card">
<div class="card-body">
<h5 class= "card-title">${comment.name}</h5>
<h6 class="card-subtitle mb-2 text-muted">${comment.title}</h6>
<div>comment: ${comment.usercomment}</div>
<hr>
</div>
</div>
</div>
`;
document.getElementById('commentsSection').innerHTML += y;
}
})
// also add a catch block
.catch(err => {
console.error('error:', err)
});
在您的main.js
文件中,删除第一个then
语句中的return
关键字。 之后,将数据数组和 append 数据循环到 HTML 元素中。
async function GetComments () {
let options = {
method: 'GET',
headers: {
'Content-Type': 'application/json'
},
};
await fetch('http://127.0.0.1:3000/comment', options)
.then(res => res.json())
.then(data => {
for (let comment of data) {
const x = `
<div class="col-4">
<div class="card">
<div class="card-body">
<h5 class= "card-title">${comment.name}</h5>
<h6 class="card-subtitle mb-2 text-muted">${comment.title}</h6>
<div>comment: ${comment.usercomment}</div>
<hr>
</div>
</div>
</div>
`;
document.getElementById('commentsSection').innerHTML =
document.getElementById('commentsSection').innerHTML + x;
}
});
}
GetComments();
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