javascript-constructors

Question 1

What does the new operator do?

Answer 1

the new operator lets a dev create instances of an object
4 things:
1. creates a blank object
2. points the __proto__ property of the newlyCreatedInstance to the .prototype property of the constructor function
3. execute the constructor function w the given arguments binding newly created instance to this (i.e any reference to this in the constructor function now refers to the newlyCreatedInstance).
4 if the constructor returns an object this becomes the value of the entire new expression but if the return is a primitive, newlyCreatedInstance is returned instead

Question 1

What property of JavaScript functions can store shared behavior for instances created with new?

Answer 1

.prototype property

Question 2

What does the instanceof operator do?

Answer 2

checks if the object has a certain prototype