Когда я запускаю вызов извлечения из моего componentDidMount() метода, он возвращает undefined. Файл PHP возвращает JSON без проблем, когда я запускаю его вручную на сервере, но сам вызов - это то, что возвращает undefined.
componentDidMount() {
fetch("backend.php").then(function (data) {
console.log("Hello");
console.log(data);
})
}
Моя консоль говорит:
App.js:60 Hello
App.js:61 undefined
Однако, если я перейду на backend.php в моем браузере, я получу
[{"ID":"0","Name":"Hulk","Publisher":"Marvel","Date":"2019-04-02","Number":"1"},{"ID":"1","Name":"Hulk","Publisher":"Marvel","Date":"2019-04-02","Number":"2"}]
Вот мой PHP-файл
$result_array = array();
/* Create connection */
$conn = new mysqli($host, $username, $password, $dbname);
/* Check connection */
if ($conn->connect_error) {
die("Connection to database failed: " . $conn->connect_error);
}
/* SQL query to get results from database */
$sql = "SELECT * FROM Comics ";
$result = $conn->query($sql);
/* If there are results from database push to result array */
if ($result->num_rows > 0) {
while($row = $result->fetch_assoc()) {
array_push($result_array, $row);
}
}
/* send a JSON encded array to client */
header('Content-Type: application/json');
echo json_encode($result_array);
$conn->close();
Из-за трудностей с выяснением этого вопроса, я добавил это для вас, ребята, чтобы увидеть. Это то, что возвращается, если я скажу, что это текст с использованием .then(response => response.text()).
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<link rel="shortcut icon" href="/favicon.ico" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js">
</script>
<meta name="viewport"
content="width=device-width, initial-scale=1, shrink-to-fit=no" />
<meta name="theme-color" content="#000000" />
<!--
manifest.json provides metadata used when your web app is installed on a
user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
-->
<link rel="manifest" href="/manifest.json" />
<!--
Notice the use of in the tags above.
It will be replaced with the URL of the `public` folder during the build.
Only files inside the `public` folder can be referenced from the HTML.
Unlike "/favicon.ico" or "favicon.ico", "/favicon.ico" will
work correctly both with client-side routing and a non-root public URL.
Learn how to configure a non-root public URL by running `npm run build`.
-->
<title>React App</title>
</head>
<body>
<noscript>You need to enable JavaScript to run this app.</noscript>
<div id="root"></div>
<!--
This HTML file is a template.
If you open it directly in the browser, you will see an empty page.
You can add webfonts, meta tags, or analytics to this file.
The build step will place the bundled scripts into the <body> tag.
To begin the development, run `npm start` or `yarn start`.
To create a production bundle, use `npm run build` or `yarn build`.
-->
<script src="/static/js/bundle.js"></script><script src="/static/js/0.chunk.js"></script><script src="/static/js/main.chunk.js"></script><script src="/main.c69debfe96d2803a0c36.hot-update.js"></script></body>
</html>