The native JavaScript fetch() API provides an asynchronous interface for fetching network resources across modern browsers and Node.js.
Basic Requests
GET Request (JSON)
async function loadUserData() {
const response = await fetch('https://api.example.com/user/1');
if (!response.ok) {
throw new Error(`HTTP error! status: ${response.status}`);
}
const data = await response.json();
return data;
}
POST Request (JSON Payload)
async function createUser(payload) {
const response = await fetch('https://api.example.com/users', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'Accept': 'application/json'
},
body: JSON.stringify(payload)
});
return await response.json();
}
Sending Form Data (multipart/form-data)
const formData = new FormData();
formData.append('username', 'alice');
formData.append('avatar', fileInput.files[0]);
// Omit Content-Type header so the browser sets boundary automatically
await fetch('/upload', {
method: 'POST',
body: formData
});
Aborting Requests (AbortController)
const controller = new AbortController();
const timeoutId = setTimeout(() => controller.abort(), 5000); // 5s timeout
try {
const res = await fetch('/data', { signal: controller.signal });
const data = await res.json();
} catch (err) {
if (err.name === 'AbortError') {
console.error('Fetch request timed out');
}
} finally {
clearTimeout(timeoutId);
}