Deep Nesting (ARCH3184)

Key typescript.quality.deep-nesting · Severity warning · Category quality

if/for/while/switch/try blocks nested beyond the threshold raise the code’s cognitive load and make flow hard to follow. Depth should be reduced with early returns (guard clauses) and extraction.

Incorrect

function handle(user?: User) {
  if (user) {
    if (user.active) {
      if (user.roles.length) {
        return user.roles[0];
      }
    }
  }
  return null;
}

Correct

function handle(user?: User) {
  if (!user || !user.active || !user.roles.length) return null;
  return user.roles[0];
}

Fix

Flatten conditions with early returns (guard clauses) and extract the inner block into a separate function.