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# Question 11

### Question

How would you determine if two objects are structurally equal (e.g., object shapes)?

### Answer

Determining structural equality means checking if two objects have the same properties and values, regardless of their order or nesting depth.

Here's a function to achieve that:

```javascript
function areStructurallyEqual(obj1, obj2) {
  // Handle cases where one or both objects are not plain objects
  if (typeof obj1 !== 'object' || typeof obj2 !== 'object') {
    return obj1 === obj2; // Primitive values should be compared directly
  }

  // Check if both objects have the same number of properties
  const keys1 = Object.keys(obj1);
  const keys2 = Object.keys(obj2);
  if (keys1.length !== keys2.length) {
    return false; 
  }

  // Compare property values recursively
  for (let i = 0; i < keys1.length; i++) {
    const key = keys1[i];
    if (!areStructurallyEqual(obj1[key], obj2[key])) {
      return false; // Mismatch found in a nested property
    }
  }

  return true; 
}

// Example usage:
const objA = { a: 1, b: { c: 2 } };
const objB = { a: 1, b: { c: 2 } };
const objC = { a: 1, b: 3 }; // Different value in property 'b'

console.log(areStructurallyEqual(objA, objB)); // true
console.log(areStructurallyEqual(objA, objC)); // false
```

**Explanation:**

1. **Base Case:** If either input isn't an object, we directly compare their values (since primitives are compared by value). 2. **Property Counts:** We ensure both objects have the same number of properties using `Object.keys()`. 3. **Recursive Comparison:**
   * For each matching property key:
     * Recursively call `areStructurallyEqual()` to compare nested objects.
     * If any recursive comparison returns `false`, we know they're not structurally equal, so return `false`.
2. **Structural Equality:** Only if all property comparisons succeed, do we return `true`, indicating structural equality.