Salesforce JavaScript Developer Practice Exam

When creating a class in JavaScript, what is autogenerated?

1. prototype

2. constructor

3. function

4. extension

The correct answer is: constructor

When a class is created in JavaScript, a constructor is automatically generated if one is not explicitly provided. The constructor is a special method for creating and initializing an object created within a class. This method is called when an instance of the class is created, allowing for any necessary setup or initial values to be assigned to the object’s properties. In JavaScript, a class can have a user-defined constructor, but if you do not define one, a default constructor is automatically created. This default constructor does not take any parameters and does not do anything other than initialize an object of that class. While prototypes are central to object-oriented programming in JavaScript, the prototype itself is not auto-generated during class creation in the same way that the constructor is, as the class itself will inherit methods and properties from its prototype. Functions can also be a part of the class, but they are not automatically generated in the same way the constructor is. The concept of "extension" does not apply in this context as there's no automatic extension mechanism occurring within a class definition. This automatic constructor generation feature makes it easier for developers to create instances of classes without worrying about explicitly defining constructors for every class.