Error Recovery Skill

Comprehensive strategies for diagnosing, fixing, and preventing errors.

Error Classification

Compile-Time Errors

Code	Type	Common Cause
TS2322	Type mismatch	Wrong type assigned
TS2345	Argument type	Wrong parameter type
TS2339	Property missing	Typo or missing interface property
TS2304	Not found	Missing import or declaration
TS2307	Module not found	Wrong path or missing package
TS7006	Implicit any	Missing type annotation
TS2531	Possibly null	Missing null check

Runtime Errors

Error	Description	Common Fix
ReferenceError	Variable not defined	Check declaration, scope
TypeError	Wrong type operation	Add null check, fix type
RangeError	Value out of range	Validate input range
SyntaxError	Invalid syntax	Check JSON, string format

Build Errors

Error	Description	Fix
Module not found	Package missing	npm install
Out of memory	Heap limit	Increase NODE_OPTIONS
Config error	Invalid config	Check tsconfig, vite.config

Test Failures

Type	Cause	Fix
Assertion	Logic error	Fix implementation or expectation
Timeout	Async issue	Add await, increase timeout
Mock error	Wrong mock setup	Fix mock configuration

Recovery Strategies

Strategy 1: Auto-Fix (Lint/Format)

# ESLint auto-fix
npx eslint . --fix

# Prettier format
npx prettier --write .

# TypeScript strict fixes
# Some can be auto-fixed with ts-fix

Strategy 2: Dependency Fix

# Reinstall dependencies
rm -rf node_modules package-lock.json
npm install

# Update specific package
npm update package-name

# Fix peer dependencies
npm install --legacy-peer-deps

Strategy 3: Type Error Fix

// TS2322: Type mismatch
// Before
const value: string = 123;
// After
const value: number = 123;

// TS2531: Possibly null
// Before
element.innerHTML = 'text';
// After
if (element) element.innerHTML = 'text';

// TS2339: Property missing
// Before
user.email
// After
if ('email' in user) user.email

Strategy 4: Runtime Error Fix

// TypeError: Cannot read property of undefined
// Before
const name = user.profile.name;
// After
const name = user?.profile?.name ?? 'Unknown';

// ReferenceError: not defined
// Check: Is it imported?
// Check: Is it in scope?
// Check: Is it spelled correctly?

Strategy 5: Test Failure Fix

// Assertion failure - debug first
console.log('Actual:', result);
console.log('Expected:', expected);

// Async timeout
test('async test', async () => {
  // Add proper awaits
  const result = await asyncOperation();
  expect(result).toBeDefined();
}, 10000); // Increase timeout if needed

// Mock not working
vi.mock('./module', () => ({
  default: vi.fn().mockReturnValue('mocked'),
}));

Recovery Protocol

┌─────────────────────────────────────────┐
│           ERROR DETECTED                │
└─────────────────┬───────────────────────┘
                  ▼
┌─────────────────────────────────────────┐
│         1. CLASSIFY ERROR               │
│  Syntax | Type | Runtime | Build | Test │
└─────────────────┬───────────────────────┘
                  ▼
┌─────────────────────────────────────────┐
│         2. IDENTIFY FIX                 │
│   Auto-fix | Manual | Delegate          │
└─────────────────┬───────────────────────┘
                  ▼
┌─────────────────────────────────────────┐
│         3. APPLY FIX                    │
│   Make minimal, targeted change         │
└─────────────────┬───────────────────────┘
                  ▼
┌─────────────────────────────────────────┐
│         4. VERIFY FIX                   │
│   tsc && eslint && npm test             │
└─────────────────┬───────────────────────┘
                  ▼
        ┌─────────┴─────────┐
        │ Fixed?            │
        └─────────┬─────────┘
          Yes     │     No
           │      │      │
           ▼      │      ▼
        ┌─────┐   │   ┌─────────────────┐
        │ Done│   │   │ Increment retry │
        └─────┘   │   │ (max 3)         │
                  │   └────────┬────────┘
                  │            ▼
                  │   ┌─────────────────┐
                  │   │ Retry < 3?      │
                  │   └────────┬────────┘
                  │      Yes   │   No
                  │       │    │    │
                  │       ▼    │    ▼
                  │   ┌──────┐ │ ┌────────┐
                  └───│Retry │ │ │Escalate│
                      └──────┘ │ └────────┘

Prevention Strategies

1. TypeScript Strict Mode - Catch errors at compile time
2. ESLint Rules - Enforce best practices
3. Pre-commit Hooks - Validate before commit
4. Unit Tests - Catch regressions
5. Code Review - Human verification