JS 4.2 Functions

Question 1

Define “function”

Answer 1

also called (a function declaration or function statement) it takes input and then returns an output. Functions consist of the function keyword, followed by the name, parameters, and then JS statements that define the function in a block of code.

Question 2

How do you call a function?

Answer 2

Type the function name, followed by parenthesis with a semi colon on the end.

Question 3

Define “return” statement

Answer 3

The return statement ends function execution and specifies a value to be returned to the function.

Question 4

Define “Parameter”

Answer 4

A parameter is a named variable passed into a function. Parameter variables are used to import arguments into functions.

Question 5

Define “Argument”

Answer 5

An argument is a value(primitive or object) passed as input to a function.

Question 6

How do you pass multiple arguments?

Answer 6

By separating each argument passed with a comma

Question 7

If we call a function expression before it’s defined, what will happen and why?

Answer 7

I’ll get an error because only function declarations are read by the engine first, everything else has to wait until it gets to that line of code.

Question 8

What is the shorthand method for arrow functions with a single parameter?

Answer 8

Omitting the parenthesis and declaring one single parameter.

Question 9

What happens if an arrow function expression has no parameters?

Answer 9

Add empty parathesis

Question 10

What can be omitted in an arrow function if all the code can be placed on a single line?

Answer 10

The ( return ) keyword. And curly braces.

Question 11

If we want to pass one argument to a parameter that accepts two, what must we do to the other?

Answer 11

Pass the ( undefined ) keyword

Question 12

Define the “throw” statement

Answer 12

The ( throw ) statement throws a user-defined exception. Execution of the current function will stop.

Question 13

Define an “Error” object

Answer 13

( Error ) objects are thrown when runtime errors occur. The Error object can also be used as a base object for user-defined exceptions.

Question 14

If an ( arrow function ) requires addition ‘multiple’ lines of processing what MUST we now add?

Answer 14

We reintroduce the ( return ) keyword and add curly braces

Question 15

What happens to NAMED arrow functions?

Answer 15

Named ( arrow functions ) are treated like variables ex: let bob = a => a + 100;