How can you determine if an object has a certain property?

In Node.js, there are several ways to check if an object has a property:

1. The in operator — checks for the presence of a property in the object or its prototypes:

if ('propertyName' in obj) {
  // property exists
}

2. The hasOwnProperty method — checks if the property exists directly on the object, excluding prototypes:

if (obj.hasOwnProperty('propertyName')) {
  // own property of the object
}

3. Checking for undefined:

if (obj.propertyName !== undefined) {
  // property exists and is not undefined
}

The choice of method depends on whether you need to consider properties from the prototype or only own properties.