Act as a Senior Front-End Engineer and a Technical Recruiter.

I will describe my current project.

Analyze it and suggest features that would make the project demonstrate real-world engineering skills.

Prioritize features that demonstrate:
- Complex state management
- Authentication and authorization
- API integration
- Error handling
- Performance optimization
- Responsive design
- Accessibility
- Testing
- Real-world business logic

Avoid generic features that only make the project look bigger.

For each feature, explain what skill it demonstrates and why a recruiter would care.

Project:
[DESCRIBE PROJECT]

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const a = [1, 2, 3];

const b = a;

b.push(4);

console.log(a);

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