Edge Case Handling and Debugging Questions

// Playwright example: emulate slow network and capture HAR
const { chromium } = require('playwright');
(async () => {
  const browser = await chromium.launch();
  const context = await browser.newContext({ recordHarPath: 'user-profile.har' });
  await context.setDefaultNavigationTimeout(45000);
  await context.route('**/api/user/*', route => route.continue());
  const page = await context.newPage();
  await context.setNetworkConditions({ offline: false, download: 50000, upload: 50000, latency: 200 });
  await page.goto('https://app.example.com/profile/123');
  await browser.close();
})();

// Cypress example: stub slow response
cy.intercept('GET', '/api/user/*', req => {
  req.on('before:response', res => {
    return new Promise(r => setTimeout(r, 500)); // delay to reproduce timeout
  });
}).as('getUser');
cy.visit('/profile/123');
cy.wait('@getUser');

// parseSafeInt: returns integer or throws descriptive Error
function parseSafeInt(input) {
  if (input === null || input === undefined) {
    throw new Error("Invalid input: value is null or undefined");
  }

  const s = String(input).trim();

  if (s === "") {
    throw new Error("Invalid input: empty string");
  }

  // Reject common mistaken formats like "1,000" or "1 000"
  if (/[,\s]/.test(s.replace(/^[+-]/, ""))) {
    throw new Error("Invalid input: contains thousand separators or spaces");
  }

  // Accept an optional + or - then digits only
  if (!/^[+-]?\d+$/.test(s)) {
    if (/^[+-]?\d*\.\d+$/.test(s)) {
      throw new Error("Invalid input: decimal values are not allowed");
    }
    throw new Error("Invalid input: contains non-numeric characters");
  }

  const n = Number(s);
  if (!Number.isSafeInteger(n)) {
    throw new Error("Invalid input: integer outside safe range (±9007199254740991)");
  }

  return n;
}

// sanitizeInput.test.js
const sanitizeInput = require('./sanitizeInput');

test('normal input: trims whitespace and keeps safe text', () => {
  expect(sanitizeInput('  hello world  ')).toBe('hello world');
});

test('empty input: returns empty string unchanged', () => {
  expect(sanitizeInput('')).toBe('');
});

test('malicious input: removes <script> tags and their content', () => {
  expect(sanitizeInput('Hi<script>alert(1)</script>Bye'))
    .toBe('HiBye');
});