Callable Values 25

Question 1

What are the two categories of functions in JS? What do they contain?

Answer 1

Ordinary function: can play several roles
- real function
- method
- constructor function
Specialized function: can play one role
- arrow function can only be a real function
- a method can only be a method
- a class can only be a constructor function

Question 2

What is an entity?

Answer 2

a JS feature as it lives in RAM. an ordinary function is an entity

Question 3

What is syntax?

Answer 3

the code we use to create an entity. function declarations are syntax

Question 4

What is a role?

Answer 4

describes how we use entities. an ordinary function can play the role real function or method or constructor

Question 5

What are the two reasons that arrow functions were added to JS?

Answer 5

cleaner/more concise syntax for creating functions
- no function keyword
- no parentheses if no parameter
- body can be a code block or an expression
they work better as real functions in methods bc of lexical this

Question 6

What does this do

Answer 6

Lets us access the receiver.. the object that the method was called on.

Question 7

What is a callback?

Answer 7

a callback is a function that gets passed as an argument to another function and is called asynchronously

Question 8

What is spread syntax?

Answer 8

const obj = {1,2,3}
console.log(…obj)
> 1,2,3
destructures values of iterable objects

Question 9

How is calling a function with .call() different than normal call syntax?

Answer 9

.call lets you specify this value.. aka it makes this go from implicit to explicit