Functions

Question 1

function showMessage() {
alert( ‘Hello everyone!’ );
}

function deceleration or expression?

Answer 1

deceleration

Question 2

let userName = ‘John’;

function showMessage() {
let message = ‘Hello, ‘ + userName;
alert(message);
}

showMessage(); // returns and why?

Answer 2

Hello, John

A variable declared inside a function is only visible inside that function.

Question 3

function showMessage() {
let message = “Hello, I’m JavaScript!”;
alert( message );
}

showMessage(); // returns? and why
alert( message ); // returns? and why?

Answer 3

Hello, I’m JavaScript!
variable in function

<– Error! The variable is local to the function
variable not accessible to function.

Question 4

A function can access an outer variable as well,

True or False

Answer 4

True

Question 5

let userName = ‘John’;
function showMessage() {
let message = userName;
alert(message);
}

showMessage(); // returns and why?

Answer 5

John

A function can access an outer variable.

Question 6

a function can access and alter a outer variable?

True or False

Answer 6

True

Question 7

let userName = ‘John’;

function showMessage() {
userName = “Bob”;

let message = ‘Hello, ‘ + userName;
alert(message);
}

alert( userName ); // returns?
showMessage();
alert( userName ); // returns?

Answer 7

John

before the function call

Bob,

the value was modified by the function

Question 8

In a function the outer variable is only used if ______

Answer 8

there’s no local one.

Question 9

let userName = ‘John’;

function showMessage() {
let userName = “Bob”;
let message = userName;
alert(message);
}

showMessage(); // returns and why?

alert( userName ); // returns and why?

Answer 9

Bob
the function will create and use its own userName

John,
unchanged, the function did not access the outer variable

Question 10

Variables declared outside of any function, such as the outer userName in the code above, are called _______

Answer 10

global

Question 11

Global variables are visible from any function unless_____

Answer 11

shadowed by locals

Question 12

_____ variables are visible from any function

Answer 12

Global

Question 13

A ______ is the variable listed inside the parentheses in the function declaration

Answer 13

parameter

Question 14

An ________ is the value that is passed to the function when it is called

Answer 14

argument

Question 15

If a function is called, but an argument is not provided, then the corresponding value becomes __________.

Answer 15

undefined

Question 16

function showCount(count) {
alert(count ?? “unknown”);
}

showCount(0); // returns?

Answer 16

0

Question 17

function showCount(count) {
alert(count ?? “unknown”);
}

showCount(null); // returns?
showCount(); // returns?

Answer 17

unknown

unknown

Question 18

function sum(a, b) {
return a + b;
}
// how to store the return in a variable named ‘result’?
alert( result ); // 3

Answer 18

let result = sum(1, 2);

Question 19

When a function directive reaches return what happens?

Answer 19

function stops and return value.

Question 20

There may be many occurrences of return in a single function.

True or false

Answer 20

true

using a conditional statement.

Question 21

A function with an empty return or without it returns ______

Answer 21

undefined

Question 22

function doNothing() { /* empty */ }

alert( doNothing() === undefined ); // returns?

Answer 22

true

Question 23

function doNothing() {
return;
}
alert( doNothing() === undefined ); // returns?

Answer 23

true

Question 24

If we want the returned expression to wrap across multiple lines, we should start it at the same line as return. Or at least put _______

Answer 24

the opening parentheses