Contekkan pada saat fetch return response (json, text, whatever)

response-fetch.js

let contentType = response.headers.get('content-type')
if (contentType.includes('application/json')) {
  return response.json()
} else if (contentType.includes('text/html')) {
  return response.text()
} else {
  throw new Error(`Sorry, content-type ${contentType} not supported`)
}