การอัปโหลดไฟล์ด้วย Fetch

const file = document.querySelector('#picker').files[0];
const data = new FormData();
data.append('avatar', file);
data.append('userId', '42');

console.log(data.has('avatar'));

async function upload(data) {
  const response = await fetch('/api/upload', {
    method: 'POST',
    body: data
  });
  console.log(response.status);
}

const response = await fetch('/api/upload', {
  method: 'POST',
  body: formData
});

console.log('browser added the boundary automatically');

async function upload(data) {
  const response = await fetch('/api/upload', { method: 'POST', body: data });
  if (!response.ok) {
    throw new Error('upload failed: ' + response.status);
  }
  const result = await response.json();
  console.log(result);
}

async function upload(data) {
  try {
    const res = await fetch('/api/upload', { method: 'POST', body: data });
    if (!res.ok) throw new Error('HTTP ' + res.status);
    console.log('uploaded');
  } catch (err) {
    console.log('error:', err.message);
  }
}

const files = document.querySelector('#picker').files;
const data = new FormData();
for (const file of files) {
  data.append('photos', file);
}

console.log(data.getAll('photos').length + ' files queued');

const response = await fetch('/api/upload', {
  method: 'POST',
  headers: { Authorization: 'Bearer token123' },
  body: formData
});

console.log(response.status);

const blob = new Blob([JSON.stringify({ ok: true })], {
  type: 'application/json'
});
const data = new FormData();
data.append('report', blob, 'report.json');

await fetch('/api/upload', { method: 'POST', body: data });
console.log('generated file sent');

const controller = new AbortController();
fetch('/api/upload', {
  method: 'POST',
  body: formData,
  signal: controller.signal
}).catch(e => console.log(e.name));

controller.abort();

async function submitForm(formEl) {
  const data = new FormData(formEl);
  const res = await fetch('/submit', { method: 'POST', body: data });
  console.log('status', res.status);
}