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async_promise_parallelism.html
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async_promise_parallelism.html
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Promise Parallelism in JavaScript</title>
<style>
button {
margin-right: 10px;
}
</style>
</head>
<body>
<!--
In this example, we have a button that demonstrates promise parallelism. The "Fetch Data in Parallel" button fetches data from two different endpoints concurrently using the Promise.all method. The fetched data is then displayed in a formatted way.
To understand the concepts, developers can interact with this example by clicking the button and observing the output.
-->
<h1>Promise Parallelism in JavaScript</h1>
<p>Click the button below to demonstrate promise parallelism:</p>
<button id="fetchParallel">Fetch Data in Parallel</button>
<pre id="output"></pre>
<script>
const output = document.getElementById('output');
const apiUrl1 = 'https://jsonplaceholder.typicode.com/todos/1';
const apiUrl2 = 'https://jsonplaceholder.typicode.com/todos/2';
function printResult(result) {
output.innerText = JSON.stringify(result, null, 2);
}
// Fetch data
function fetchData(url) {
return new Promise((resolve, reject) => {
fetch(url)
.then(response => {
if (!response.ok) {
throw new Error(`HTTP error: ${response.status}`);
}
return response.json();
})
.then(data => resolve(data))
.catch(error => reject(error));
});
}
document.getElementById('fetchParallel').addEventListener('click', () => {
Promise.all([
fetchData(apiUrl1),
fetchData(apiUrl2)
]).then(([data1, data2]) => {
printResult({ data1, data2 });
}).catch(error => {
output.innerText = `Error: ${error.message}`;
});
});
</script>
</body>
</html>