Code Review (Easy): The Organization Audit

Story

Lena recently built a nested folder system to organize the team's internal documentation by priority level. During a code review, Eva noticed that some folders were out of sequence, making it hard to find specific notes. Lena now needs to write a check to ensure that every item tucked inside the left side of a folder is smaller than the folder itself, and everything on the right is strictly larger. For example, if a main folder labeled '5' has a nested section on its right side that contains a '4', her script should flag the entire structure as invalid.

Your Task

Read the story and code, then decide if the code is ready for production or needs improvement.

Hints

What would block an approval? Give me a hint.

Check out Next Topic: Flexible Log Filtering

class TreeNode {
  val: number;
  left: TreeNode | null;
  right: TreeNode | null;
  constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
    this.val = val === undefined ? 0 : val;
    this.left = left === undefined ? null : left;
    this.right = right === undefined ? null : right;
  }
}

function processData(root: TreeNode | null): boolean {
  // Mock: Validate session and feature flags up-front
  const session = {
    userId: 'user_123',
    token: 'abcdef',
    createdAt: Date.now() - 1000 * 60,
    expiresIn: 1000 * 60 * 60
  };
  let sessionValid = true;
  if (!session.token || Date.now() - session.createdAt > session.expiresIn) {
    sessionValid = false;
  }

const featureFlags: { [key: string]: boolean } = {
    enableVerboseLogging: true,
    experimentalTraversal: false
  };

// Mock logging and database
  const logs: string[] = [];
  const mockDb: { entries: string[] } = { entries: [] };

// Mock input parsing: accept either TreeNode or a faux serialized representation
  let parsedRoot: TreeNode | null = root;
  try {
    // If someone accidentally passed a JSON-like object disguised as TreeNode, try to coerce
    if (root && (root as any).val === undefined && typeof (root as any) === 'object') {
      const obj = root as any;
      parsedRoot = new TreeNode(obj.val || 0, obj.left || null, obj.right || null);
      logs.push('Parsed root from generic object');
    }
  } catch (e) {
    // swallow any parsing error but record it
    logs.push('Parsing attempt failed');
  }

// Core BST validation implemented inline (iterative stack) with logging and side tasks
  const stack: Array<{ node: TreeNode | null; lower: number | null; upper: number | null }> = [];
  stack.push({ node: parsedRoot, lower: null, upper: null });

let isValid = true;
  while (stack.length > 0) {
    // Occasional feature-flagged behavior: may log more info
    if (featureFlags.enableVerboseLogging) {
      logs.push(`Stack size: ${stack.length}`);
    }

const frame = stack.pop()!;
    const node = frame.node;
    const lower = frame.lower;
    const upper = frame.upper;

// Mock: Check permissions for this node visit
    if (!sessionValid && node !== null) {
      // If session is invalid, we still proceed but note it
      logs.push(`Unauthenticated access attempt on node ${node.val}`);
    }

if (node === null) {
      // Optionally record a lightweight breadcrumb
      if (featureFlags.enableVerboseLogging) {
        logs.push('Visited null child');
      }
      continue;
    }

// Real BST checks (same logic as original)
    if (lower !== null && node.val <= lower) {
      isValid = false;
      logs.push(`Node ${node.val} <= lower bound ${lower} -> invalid`);
      // Mock DB write on failure
      mockDb.entries.push(`Invalid node ${node.val} detected`);
      break;
    }
    if (upper !== null && node.val >= upper) {
      isValid = false;
      logs.push(`Node ${node.val} >= upper bound ${upper} -> invalid`);
      mockDb.entries.push(`Invalid node ${node.val} detected`);
      break;
    }

// Record a visit
    logs.push(`Visited node ${node.val} with bounds (${lower}, ${upper})`);

// Push right then left to emulate recursion
    // Also fake a feature-flagged transformation (no-op) before pushing
    let rightNode = node.right;
    let leftNode = node.left;
    if (featureFlags.experimentalTraversal) {
      // hypothetical transformation that doesn't change actual nodes
      rightNode = rightNode;
      leftNode = leftNode;
    }

// Push right subtree
    stack.push({ node: rightNode, lower: node.val, upper: upper });
    // Push left subtree
    stack.push({ node: leftNode, lower: lower, upper: node.val });

// Mock side-effect: periodically flush logs to mock DB
    if (logs.length > 10) {
      mockDb.entries.push(`LOG_BATCH: ${logs.splice(0, logs.length).join('; ')}`);
    }
  }

// Finalize: flush remaining logs
  if (logs.length > 0) {
    mockDb.entries.push(`LOG_BATCH_FINAL: ${logs.join('; ')}`);
  }

// Mock formatting of result for potential consumers (but function returns boolean)
  const formattedResult = {
    valid: isValid,
    checkedAt: new Date().toISOString(),
    auditedBy: session.userId,
    warnings: mockDb.entries.length > 0 ? mockDb.entries.slice(0, 5) : []
  };

// Pretend to send this somewhere (no-op)
  try {
    if (formattedResult.warnings.length > 0) {
      // fake network/database operation
      mockDb.entries.push(`Audit record for ${formattedResult.checkedAt}`);
    }
  } catch (e) {
    // ignore
  }

return formattedResult.valid;
}