Terminal Interaction

/**
 * Clears the current line in a TTY stream
 * @param stream - The TTY write stream to clear
 */
function clearLine(stream: WriteStream): void;

import { clearLine } from "jest-util";

// Clear current line in stdout
clearLine(process.stdout);

// Clear current line in stderr  
clearLine(process.stderr);

// Progress indicator with line clearing
function showProgress(current: number, total: number) {
  clearLine(process.stdout);
  process.stdout.write(`Progress: ${current}/${total} (${Math.round(current/total * 100)}%)`);
}

// Jest test runner progress
function updateTestProgress(completed: number, total: number) {
  if (process.stdout.isTTY) {
    clearLine(process.stdout);
    process.stdout.write(`Tests: ${completed}/${total} completed`);
  }
}

// Dynamic status updates
let dots = 0;
const statusInterval = setInterval(() => {
  if (process.stdout.isTTY) {
    clearLine(process.stdout);
    process.stdout.write(`Running tests${'.'.repeat(dots % 4)}`);
    dots++;
  }
}, 500);

/**
 * Boolean indicating if environment supports interactive features
 */
const isInteractive: boolean;

import { isInteractive } from "jest-util";

// Conditional interactive features
if (isInteractive) {
  console.log("Running in interactive mode");
  // Show progress bars, colored output, etc.
} else {
  console.log("Running in non-interactive mode"); 
  // Plain text output for CI/CD
}

// Jest watch mode detection
function shouldEnableWatchMode(): boolean {
  return isInteractive && !process.env.CI;
}

// Progress reporting
function reportProgress(current: number, total: number) {
  if (isInteractive) {
    // Show dynamic progress bar
    clearLine(process.stdout);
    process.stdout.write(`[${'='.repeat(current)}${' '.repeat(total-current)}] ${current}/${total}`);
  } else {
    // Log discrete progress updates
    if (current % 10 === 0) {
      console.log(`Progress: ${current}/${total}`);
    }
  }
}

/**
 * Collection of special characters for terminal output
 */
const specialChars: {
  /** Arrow character for indicating direction or selection */
  ARROW: string;
  /** Status icons for test results */
  ICONS: {
    /** Cross mark for failed tests */
    failed: string;
    /** Circle for pending tests */ 
    pending: string;
    /** Check mark for successful tests */
    success: string;
    /** Pencil for todo items */
    todo: string;
  };
  /** ANSI clear screen sequence */
  CLEAR: string;
};

import { specialChars } from "jest-util";

// Test result formatting
function formatTestResult(status: 'passed' | 'failed' | 'pending' | 'todo', name: string) {
  let icon: string;
  switch (status) {
    case 'passed': icon = specialChars.ICONS.success; break;
    case 'failed': icon = specialChars.ICONS.failed; break;
    case 'pending': icon = specialChars.ICONS.pending; break;
    case 'todo': icon = specialChars.ICONS.todo; break;
  }
  
  return `${icon} ${name}`;
}

// Examples:
// formatTestResult('passed', 'should add numbers') → "✓ should add numbers"
// formatTestResult('failed', 'should handle errors') → "✗ should handle errors"

// Navigation indicators
function showSelected(items: string[], selectedIndex: number) {
  items.forEach((item, index) => {
    const prefix = index === selectedIndex ? specialChars.ARROW : '  ';
    console.log(`${prefix} ${item}`);
  });
}

// Clear screen for fresh output
function clearScreen() {
  process.stdout.write(specialChars.CLEAR);
}

// Test suite header
function printTestSuiteHeader() {
  clearScreen();
  console.log(`${specialChars.ICONS.success} Jest Test Suite`);
  console.log(`${specialChars.ARROW} Running tests...`);
}

/**
 * Pre-run message utilities for Jest initialization
 */
const preRunMessage: {
  /** Display the pre-run message in interactive mode */
  print(stream: WriteStream): void;
  /** Clear the pre-run message in interactive mode */
  remove(stream: WriteStream): void;
};

import { preRunMessage } from "jest-util";

// Jest initialization sequence
function initializeTestRun() {
  // Show loading message
  preRunMessage.print(process.stdout);
  
  // Perform test discovery and setup
  await discoverTestFiles();
  await setupTestEnvironment();
  
  // Clear loading message before starting tests
  preRunMessage.remove(process.stdout);
  
  console.log("Starting test execution...");
}

// Custom loading sequence
function showInitializationProgress() {
  preRunMessage.print(process.stdout);
  
  setTimeout(() => {
    preRunMessage.remove(process.stdout);
    console.log("Initialization complete!");
  }, 2000);
}

// Conditional message display
function conditionalPreRunMessage() {
  if (process.env.VERBOSE !== 'true') {
    preRunMessage.print(process.stdout);
    
    // Later, after setup is complete
    preRunMessage.remove(process.stdout);
  }
}

// Node.js WriteStream interface
interface WriteStream {
  write(chunk: any): boolean;
  isTTY?: boolean;
}