error-resolver

预期结果:

Classification: Dependency / Error / Build-time

Root Cause: The express package is not installed in node_modules or is missing from package.json.

Immediate Fix:
1. Run: npm install express
2. Verify: Check that express appears in node_modules

Proper Fix:
1. Add express to package.json dependencies
2. Run: npm install
3. Commit package.json and package-lock.json

Prevention:
- Always run npm install after cloning
- Use npm ci in CI/CD pipelines
- Add dependencies via npm install --save, not manual edits

预期结果:

Classification: Type / Error / Runtime

Root Cause Analysis (5 Whys):
- Why 1? The object is undefined
- Why 2? API call returned null instead of object
- Why 3? User ID does not exist in database
- Why 4? Stale cache contained invalid ID
- Why 5? Cache invalidation not implemented

Solution: Add null check before property access and implement cache invalidation.

Code Change:
if (user && user.name) {
console.log(user.name);
} else {
console.log(User not found);
}

Prevention: Add TypeScript for compile-time type checking