HTTP Status Codes

const response = await fetch("/api/users/123");
console.log(response.status); // 200
console.log(response.ok);     // true (status 200-299)

// Handling success codes
async function createUser(data) {
  const res = await fetch("/api/users", {
    method: "POST",
    body: JSON.stringify(data)
  });

  if (res.status === 201) {
    const user = await res.json();
    console.log("Created:", user.id);
  }
}

// Handling client errors
async function getUser(id) {
  const res = await fetch(`/api/users/${id}`);

  switch (res.status) {
    case 200:
      return res.json();
    case 401:
      throw new Error("Please log in");
    case 403:
      throw new Error("You don't have permission");
    case 404:
      return null; // User doesn't exist
    case 429:
      throw new Error("Too many requests, try again later");
    default:
      throw new Error(`Request failed: ${res.status}`);
  }
}

// Handling server errors with retry
async function fetchWithRetry(url, retries = 3) {
  for (let i = 0; i < retries; i++) {
    const res = await fetch(url);

    if (res.status >= 500) {
      // Server error - wait and retry
      await new Promise(r => setTimeout(r, 1000 * (i + 1)));
      continue;
    }

    return res;
  }
  throw new Error("Server unavailable after retries");
}