Factory Functions & Singleton Pattern

What key difference exists between these two approaches?

function Circle(radius) {
  this.radius = radius;
  this.area = function() {
    return Math.PI * this.radius * this.radius;
  };
}

function createCircle(radius) {
  return {
    radius,
    area: function() {
      return Math.PI * radius * radius;
    }
  };
}

Performance
Memory usage
The factory function doesn't rely on 'this'
A key difference is that the factory function doesn't rely on 'this': 1) The factory function uses closure to access radius, not 'this', 2) This makes the area method more reliable in contexts where 'this' might change, 3) Methods from the factory can be safely passed as callbacks without binding, 4) The factory approach avoids common 'this' binding issues in JavaScript, 5) The constructor function requires proper invocation with 'new', 6) This difference highlights why factories can be more robust in certain JavaScript contexts.
The constructor creates more features

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