Functions

Question 1

ES6 distinguishes between 2 types of functions. What are they?

Answer 1

Callable (cannot be called with new) Constructable (can be called with new, return an object)

Question 2

Functions created via the arrow function syntax or via a method definition / object literals are not ….

Answer 2

Constructable

Question 3

When I create a function, how do I make it NOT a constructor?

Answer 3

To create a function that is not constructable, you can use an arrow function.

Question 4

What is the default return value of a function?

Answer 4

Undefined

Question 5

When defining a function, the identifiers that are placed within the brackets are called …

Answer 5

Parameters

Question 6

When identifiers or variables are passed into a function for execution, they are known as …

Answer 6

Arguments

Question 7

What are 4 unique properties of an arrow function?

Answer 7

1. It does not have its own this
2. It does not have its own arguments
3. It does not its own super
4. It does not have its own new.target

Question 8

Can arrow functions be used as constructors?

Answer 8

No. They are callable, not constructable. They do not pass on a this context.

Question 9

If arrow functions do not have their own this value, how does this take its value within the function?

Answer 9

The this value of the enclosing lexical scope is used, e.g. arrow functions follow the normal variable lookup rules.

Question 10

What 4 steps happen automatically when invoking a function as a constructor?

Answer 10

1. ) A new object is created (O)
2. ) the new object is [[Prototype]]-linked (P)
3. ) the new object is set as the ThisBinding for the function’s execution context (E)
4. ) the new object is returned* (N)

O.P.E.N.

* Unless the function overrides this with its own explicit return