인터페이스 해부: 객체 타입 계약

// interface 시뮬레이션
  function validateTerminator(unit) {
    const required = ['model', 'threat'];
    const optional = ['status', 'location'];
    const readonly = ['id'];
    let valid = true;
    const results = [];
    required.forEach(k => {
      if (unit[k] === undefined) { valid = false; results.push(`❌ 필수 속성 누락: ${k}`); }
      else results.push(`✓ ${k}: ${unit[k]}`);
    });
    optional.forEach(k => results.push(`? ${k}: ${unit[k] ?? '(없음)'}`) );
    readonly.forEach(k => results.push(`🔒 readonly ${k}: ${unit[k]}`) );
    results.forEach(r => {
      const el = document.createElement('div');
      el.style.fontSize = '11px'; el.style.marginBottom = '4px'; el.style.color = r.startsWith('❌') ? '#10b981' : r.startsWith('✓') ? '#22c55e' : '#888';
      el.textContent = r;
      document.currentScript.parentElement.appendChild(el);
    });
  }
  // interface Terminator { readonly id: number; model: string; threat: number; status?: string; location?: string; }
  validateTerminator({ id: 1, model: 'T-800', threat: 8, status: 'ACTIVE' });