Network & Fetch

const fetch = require('fbjs/lib/fetch');

/**
 * Fetch API implementation
 * Uses global.fetch if available, otherwise cross-fetch polyfill
 * 
 * @param input - URL string or Request object
 * @param init - Optional request configuration
 * @returns Promise that resolves to Response object
 */
function fetch(input: string | Request, init?: RequestInit): Promise<Response>;

// RequestInit interface for configuration
interface RequestInit {
  method?: string;           // HTTP method (GET, POST, PUT, DELETE, etc.)
  headers?: Headers | Object; // Request headers
  body?: BodyInit;           // Request body (string, FormData, etc.)
  mode?: RequestMode;        // CORS mode (cors, no-cors, same-origin)
  credentials?: RequestCredentials; // Credentials mode (omit, same-origin, include)
  cache?: RequestCache;      // Cache mode (default, no-store, reload, etc.)
  redirect?: RequestRedirect; // Redirect mode (follow, error, manual)
  referrer?: string;         // Referrer
  referrerPolicy?: ReferrerPolicy; // Referrer policy
  integrity?: string;        // Subresource integrity
  signal?: AbortSignal;      // AbortController signal for cancellation
}

// Response interface
interface Response {
  ok: boolean;              // True if status in 200-299 range
  status: number;           // HTTP status code
  statusText: string;       // HTTP status text
  headers: Headers;         // Response headers
  url: string;             // Response URL
  redirected: boolean;      // True if response is result of redirect
  type: ResponseType;       // Response type (basic, cors, error, etc.)
  
  // Body parsing methods
  text(): Promise<string>;
  json(): Promise<any>;
  blob(): Promise<Blob>;
  arrayBuffer(): Promise<ArrayBuffer>;
  formData(): Promise<FormData>;
  
  // Body stream
  body: ReadableStream;
  bodyUsed: boolean;
  
  // Cloning
  clone(): Response;
}

const fetch = require('fbjs/lib/fetch');

// Simple GET request
fetch('https://api.example.com/users')
  .then(response => {
    if (!response.ok) {
      throw new Error(`HTTP ${response.status}: ${response.statusText}`);
    }
    return response.json();
  })
  .then(users => {
    console.log('Users:', users);
  })
  .catch(error => {
    console.error('Fetch error:', error);
  });

// POST request with JSON data
const newUser = {
  name: 'Alice Johnson',
  email: 'alice@example.com'
};

fetch('https://api.example.com/users', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'Authorization': 'Bearer ' + token
  },
  body: JSON.stringify(newUser)
})
  .then(response => response.json())
  .then(createdUser => {
    console.log('Created user:', createdUser);
  });

// Request with AbortController for cancellation
const controller = new AbortController();
const signal = controller.signal;

// Cancel request after 5 seconds
setTimeout(() => controller.abort(), 5000);

fetch('https://api.example.com/large-data', { signal })
  .then(response => response.json())
  .catch(error => {
    if (error.name === 'AbortError') {
      console.log('Request was cancelled');
    } else {
      console.error('Request failed:', error);
    }
  });

// Upload file with FormData
const formData = new FormData();
formData.append('file', fileInput.files[0]);
formData.append('description', 'Profile picture');

fetch('https://api.example.com/upload', {
  method: 'POST',
  body: formData
})
  .then(response => response.json());

const fetchWithRetries = require('fbjs/lib/fetchWithRetries');

/**
 * Fetch with automatic retry logic for failed requests
 * @param uri - URL to fetch
 * @param initWithRetries - Request configuration with retry options
 * @returns Promise that resolves to Response object
 */
function fetchWithRetries(uri: string, initWithRetries?: RequestInitWithRetries): Promise<Response>;

// Extended RequestInit with retry configuration
interface RequestInitWithRetries extends RequestInit {
  // Standard fetch options
  method?: string;
  headers?: Headers | Object;
  body?: BodyInit;
  mode?: RequestMode;
  credentials?: RequestCredentials;
  cache?: RequestCache;
  redirect?: RequestRedirect;
  
  // Retry-specific options
  retries?: number;         // Maximum number of retry attempts (default: 3)
  retryDelayType?: 'fixed' | 'linear' | 'exponential'; // Delay strategy (default: 'exponential')
  retryDelayMS?: number;    // Base delay in milliseconds (default: 1000)
  retryDelayMax?: number;   // Maximum delay in milliseconds (default: 10000)
  shouldRetry?: (error: Error, attempt: number) => boolean; // Custom retry predicate
  onRetryAttempt?: (attempt: number, delay: number) => void; // Retry attempt callback
}

const fetchWithRetries = require('fbjs/lib/fetchWithRetries');

// Basic retry with default settings (3 retries, exponential backoff)
fetchWithRetries('https://api.example.com/unreliable-endpoint')
  .then(response => response.json())
  .then(data => {
    console.log('Data received after retries:', data);
  })
  .catch(error => {
    console.error('Failed after all retries:', error);
  });

// Custom retry configuration
fetchWithRetries('https://api.example.com/data', {
  method: 'GET',
  headers: {
    'Authorization': 'Bearer ' + token
  },
  retries: 5,                    // Try up to 5 times
  retryDelayType: 'linear',      // Linear delay increase
  retryDelayMS: 500,             // Start with 500ms delay
  retryDelayMax: 5000,           // Max 5 second delay
  shouldRetry: (error, attempt) => {
    // Only retry on network errors or 5xx status codes
    return error.name === 'TypeError' || 
           (error.status && error.status >= 500);
  },
  onRetryAttempt: (attempt, delay) => {
    console.log(`Retry attempt ${attempt} after ${delay}ms delay`);
  }
})
  .then(response => {
    console.log('Request succeeded on attempt:', response);
  });

// Retry with exponential backoff for POST requests
const postData = { message: 'Important data' };

fetchWithRetries('https://api.example.com/messages', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json'
  },
  body: JSON.stringify(postData),
  retries: 3,
  retryDelayType: 'exponential',
  retryDelayMS: 1000,           // 1s, 2s, 4s delays
  shouldRetry: (error, attempt) => {
    // Don't retry client errors (4xx), only server errors (5xx) and network issues
    if (error.status) {
      return error.status >= 500;
    }
    return true; // Network error, retry
  }
})
  .then(response => response.json())
  .then(result => {
    console.log('Message sent successfully:', result);
  })
  .catch(error => {
    console.error('Failed to send message after retries:', error);
  });

const xhrSimpleDataSerializer = require('fbjs/lib/xhrSimpleDataSerializer');

/**
 * Serializes data for XHR requests into URL-encoded format
 * @param data - Data object to serialize
 * @returns URL-encoded string representation of data
 */
function xhrSimpleDataSerializer(data: any): string;

const xhrSimpleDataSerializer = require('fbjs/lib/xhrSimpleDataSerializer');

// Serialize object for form submission
const formData = {
  username: 'alice@example.com',
  password: 'secret123',
  remember: true,
  preferences: ['email', 'sms']
};

const serialized = xhrSimpleDataSerializer(formData);
console.log(serialized);
// Output: "username=alice%40example.com&password=secret123&remember=true&preferences=email&preferences=sms"

// Use with traditional XMLHttpRequest
const xhr = new XMLHttpRequest();
xhr.open('POST', 'https://api.example.com/login');
xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
xhr.send(serialized);

// Use with fetch for form-encoded POST
const loginData = {
  email: 'user@example.com',
  password: 'mypassword'
};

fetch('https://api.example.com/auth/login', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/x-www-form-urlencoded'
  },
  body: xhrSimpleDataSerializer(loginData)
})
  .then(response => response.json());

// Handle nested objects and arrays
const complexData = {
  user: {
    name: 'John Doe',
    age: 30
  },
  tags: ['developer', 'javascript'],
  active: true
};

const complexSerialized = xhrSimpleDataSerializer(complexData);
// Handles nested structures appropriately for form encoding

const DataTransfer = require('fbjs/lib/DataTransfer');
const PhotosMimeType = require('fbjs/lib/PhotosMimeType');

/**
 * Data transfer utilities for drag-and-drop and clipboard operations
 */
class DataTransfer {
  /**
   * Creates a new DataTransfer instance
   */
  constructor();
  
  /**
   * Gets files from transfer operation
   * @returns Array of File objects
   */
  getFiles(): Array<File>;
  
  /**
   * Gets text data from transfer
   * @param format - MIME type or format (e.g., 'text/plain', 'text/html')
   * @returns Text data or null if not available
   */
  getData(format: string): ?string;
  
  /**
   * Sets text data for transfer
   * @param format - MIME type or format
   * @param data - Text data to set
   */
  setData(format: string, data: string): void;
  
  /**
   * Checks if specific data type is available
   * @param format - MIME type or format to check
   * @returns True if data type is available
   */
  hasType(format: string): boolean;
  
  /**
   * Gets list of available data types
   * @returns Array of available MIME types/formats
   */
  getTypes(): Array<string>;
  
  /**
   * Clears all data from transfer
   */
  clearData(): void;
}

/**
 * Photo and image MIME type utilities
 */
const PhotosMimeType: {
  /**
   * Checks if MIME type is a supported image format
   * @param mimeType - MIME type string
   * @returns True if MIME type represents an image
   */
  isImage(mimeType: string): boolean;
  
  /**
   * Checks if MIME type is a photo format (excludes SVG, etc.)
   * @param mimeType - MIME type string
   * @returns True if MIME type is a photo format
   */
  isPhoto(mimeType: string): boolean;
  
  /**
   * Gets file extension for MIME type
   * @param mimeType - Image MIME type
   * @returns File extension (e.g., 'jpg', 'png') or null
   */
  getExtension(mimeType: string): ?string;
  
  /**
   * Gets MIME type for file extension
   * @param extension - File extension (with or without dot)
   * @returns MIME type string or null
   */
  getMimeType(extension: string): ?string;
  
  /**
   * Gets list of supported image MIME types
   * @returns Array of supported MIME type strings
   */
  getSupportedTypes(): Array<string>;
  
  /**
   * Validates if file is an acceptable image format
   * @param file - File object to validate
   * @returns True if file is acceptable image format
   */
  isValidImageFile(file: File): boolean;
};

const DataTransfer = require('fbjs/lib/DataTransfer');
const PhotosMimeType = require('fbjs/lib/PhotosMimeType');

// Handle drag and drop
function handleDrop(event) {
  const transfer = new DataTransfer();
  const files = transfer.getFiles();
  
  files.forEach(file => {
    if (PhotosMimeType.isPhoto(file.type)) {
      console.log('Dropped photo:', file.name);
      // Process photo file
    } else {
      console.log('Not a photo format:', file.type);
    }
  });
  
  // Get text data if available
  const htmlContent = transfer.getData('text/html');
  const plainText = transfer.getData('text/plain');
}

// MIME type validation
const mimeTypes = ['image/jpeg', 'image/png', 'image/svg+xml', 'text/plain'];

mimeTypes.forEach(type => {
  console.log(`${type}:`);
  console.log(`  Is image: ${PhotosMimeType.isImage(type)}`);
  console.log(`  Is photo: ${PhotosMimeType.isPhoto(type)}`);
  console.log(`  Extension: ${PhotosMimeType.getExtension(type)}`);
});

// File upload validation
function validateImageUpload(file) {
  if (!PhotosMimeType.isValidImageFile(file)) {
    throw new Error('Invalid image file type');
  }
  
  if (PhotosMimeType.isPhoto(file.type)) {
    console.log('Uploading photo:', file.name);
  } else {
    console.log('Uploading image:', file.name);
  }
}

// Get supported formats for file input
const supportedTypes = PhotosMimeType.getSupportedTypes();
const accept = supportedTypes.join(',');
// Use in HTML: <input type="file" accept="image/jpeg,image/png,..." />