Functions

Question 1

Functions that are part of objects are called ________.

Answer 1

methods

Question 2

function hello(name = ‘Chris’) {
console.log(Hello ${name}!);
}

hello(‘Ari’); returns?
hello(); returns

Answer 2

// Hello Ari!
// Hello Chris!

Question 3

Unlike function declaration, function expressions are ___________

Answer 3

not hoisted

Question 4

Unlike function declaration, ___________ are not hoisted

Answer 4

function expressions

Question 5

if your arrow function needs to return a value, and contains only one line, you can also omit the__________.

Answer 5

return statement

Question 6

Arrow functions don’t have their own bindings to ____ , ______ ,______ and should not be used as methods.

Answer 6

this, arguments, or super,

Question 7

Arrow functions cannot be used as _________. Calling them with new throws a _________ . T

Answer 7

constructors
TypeError

Question 8

Arrow functions cannot use ________ within their body and cannot be created as generator functions.

Answer 8

Yield

Question 9

// Traditional anonymous function
(function (a) {
return a + 100;
});

write as arrow

Answer 9

a => a+100;

Question 10

// Traditional anonymous function
(function (a, b) {
return a + b + 100;
});

write as arrow

Answer 10

(a, b) => a + b + 100;

Question 11

// Traditional anonymous function (no parameters)
(function () {
return a + b + 100;
});

write as arrow

Answer 11

() => a + b + 100;

Question 12

// Traditional anonymous function
(function (a, b) {
const chuck = 42;
return a + b + chuck;
});

write as arrow

Answer 12

// Arrow function

(a, b) => {
const chuck = 42;
return a + b + chuck;
};

Question 13

If the arrow function needs to call itself, use a named ____________ instead.

Answer 13

function expression

Question 14

// Traditional Function
function bob(a) {
return a + 100;
}

write as arrow

Answer 14

const bob2 = (a) => a + 100;

Question 15

const func2 = (x, y) => {

};

what is missing

Answer 15

return x + y;

In a concise body, only a single expression is specified, which becomes the implicit return value. In a block body, you must use an explicit return statement.

Question 16

const func = () => { foo: 1 };
// Calling func() returns undefined!

how to fix?

Answer 16

const func = () => ({ foo: 1 });

Question 17

For similar reasons, the_______, _______, _______methods are not useful when called on arrow functions, because arrow functions establish this based on the scope the arrow function is defined within, and the this value does not change based on how the function is invoked.

Answer 17

call(), apply(), and bind()

Question 18

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

function expression or function declaration.?

Answer 18

function declaration.

Question 19

let userName = ‘John’;

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

showMessage(); returns?

Answer 19

// Hello, John

Question 20

let userName = ‘John’;

function showMessage() {
userName = “Bob”; /

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

alert( userName );
showMessage();
alert( userName );

Answer 20

// John before the function call

// Bob, the value was modified by the function

Question 21

let userName = ‘John’;

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

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

Answer 21

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

Question 22

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

Answer 22

global.

Question 23

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

Answer 23

undefined

Question 24

We can specify the so-called “default” (to use if omitted) value for a parameter in the function declaration, using _______:

Answer 24

=

Question 25

function showMessage(from, _______) {
alert( from + “: “ + text );
}
showMessage(“Ann”);

what to write if you want default value “no text given”

Answer 25

function showMessage(from, text = “no text given”) {
alert( from + “: “ + text );
}

Question 26

function showMessage(from, text) {
if (//_____ insert here) {
text = ‘no text given’;
}

insert text to check if undfined

Answer 26

function showMessage(from, text) {
if (text === undefined) {
text = ‘no text given’;
}

Question 27

function showMessage(from, text) {

…
}

insert text to check undefined using and operator ||

Answer 27

text = text || ‘no text given’;

Question 28

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

showCount(0);
showCount(null);
showCount();

Answer 28

showCount(0); // 0
showCount(null); // unknown
showCount(); // unknown

Question 29

It is possible to use return without a value. That causes the function to ____________

Answer 29

exit immediately.

Question 30

If a function does not return a value, it is the same as if it returns __________:

Answer 30

undefined

Question 31

function doNothing() {
return;
}
alert( doNothing() === undefined );

above returns?

Answer 31

true

Question 32

function doNothing() {
return;
}

the above returns

Answer 32

undefined

Question 33

function checkAge(age) {
if (age > 18) {
return true;
} else {
return confirm(‘Did parents allow you?’);
}
}

write both using || &&

Answer 33

function checkAge(age) {
return (age > 18) ? true : confirm(‘Did parents allow you?’);
}

function checkAge(age) {
return (age > 18) || confirm(‘Did parents allow you?’);
}

Question 34

function min(a, b) {
return a < b ? a : b;
}

write using if else

Answer 34

function min(a, b) {
if (a < b) {
return a;
} else {
return b;
}
}

Question 35

function min(a, b) {
if (a < b) {
return a;
} else {
return b;
}
}

write using ?

Answer 35

function min(a, b) {
return a < b ? a : b;
}

Question 36

let sayHi = function() {
alert( “Hello” );
};

above decleration or expresssion?

Answer 36

Function Expression

Question 37

there’s no name after the function keyword in a function ________

Answer 37

expression

Question 38

function sayHi() {
alert( “Hello” );
}

alert( sayHi );

Answer 38

// shows the function code

Question 39

Function ________ have a semicolon ; at the end, but Function ________ do not:

Answer 39

Function Expressions

Declarations

Question 40

A Function ________ is created when the execution reaches it and is usable only from that moment.

Answer 40

Expression

Question 41

A Function _________ can be called earlier than it is defined.

Answer 41

Declaration

Question 42

sayHi(“John”);

function sayHi(name) {
alert( Hello, ${name} );
}

Answer 42

// Hello, John

Question 43

sayHi(“John”);

let sayHi = function(name) {
alert( Hello, ${name} );
};

Answer 43

// error!

Question 44

Function _________ are created when the execution reaches them. That would happen only in the line (*). Too late.

Answer 44

Expressions

Question 45

That’s because a Function ________ is only visible inside the code block in which it resides.

Answer 45

Declaration

Question 46

As a rule of thumb, when we need to declare a function, the first thing to consider is _________ syntax

Answer 46

Function Declaration

Question 47

Function __________ are processed before the code block is executed. They are visible everywhere in the block.

Answer 47

Declarations

Question 48

let double = function(n) { return n * 2 }

write as an arrow

Answer 48

let double = n => n * 2;

Question 49

Sometimes we need a more complex function, with multiple expressions and statements. In that case, we can enclose them in curly braces. The major difference is that curly braces require a_________

Answer 49

return

Question 50

Sometimes we need a more complex function, with multiple expressions and statements. In that case, we can enclose them in ________ The major difference is that curly braces require a return

Answer 50

curly braces.

Question 51

function ask(question, yes, no) {
if (confirm(question)) yes();
else no();
}

ask(
“Do you agree?”,
function() { alert(“You agreed.”); },
function() { alert(“You canceled the execution.”); }
);

Answer 51

function ask(question, yes, no) {
if (confirm(question)) yes();
else no();
}

ask(
“Do you agree?”,
() => alert(“You agreed.”),
() => alert(“You canceled the execution.”)
);

Question 52

arrow functions can’t be used as ________. They can’t be called with new.

Answer 52

constructors.

Question 53

arrow functions can’t be used as constructors. They can’t be called with ______.

Answer 53

news

Question 54

Arrow functions:

Do not have \_\_\_\_
Do not have \_\_\_\_\_\_
Can’t be called with \_\_\_\_

Answer 54

this`
arguments
new

Question 55

The ________ keyword refers to the object that the function is accessed on — it does not refer to the currently executing function, so you must refer to the function value by name, even within the function body.

Answer 55

this

Question 56

JavaScript has four kinds of functions

Answer 56

Regular
Generator
Async
Async generator

Question 57

const multiply = new Function(“x”, “y”, “return x * y”);

what type of function?

Answer 57

constructor

Question 58

function multiply(x, y) {
return x * y;

what type of function?

Answer 58

Declaration

Question 59

const multiply = function (x, y) {
return x * y;

what type of function?

Answer 59

Expression

Question 60

const obj = {
multiply(x, y) {
return x * y;
},
};

what type of function?

Answer 60

Method

Question 61

The Function() constructor, function expression, and function declaration syntaxes create full-fledged function objects, which can be constructed with ______.

Answer 61

new

Question 62

The Function() ______, _____, _______, and function declaration syntaxes create full-fledged function objects, which can be constructed with new.

Answer 62

constructor, expression, and declaration

Question 63

The function _______ creates functions that are hoisted.

Answer 63

declaration

Question 64

The ______ function and Function() _______ always create anonymous functions, which means they can’t easily call themselves recursively.

Answer 64

arrow
constructor

Question 65

three special function parameter syntaxes:

Answer 65

-defualt
-rest (…rest)
-deconstructing: allows unpacking elements from arrays, or properties from objects, into distinct variables.

Question 66

In ________ functions inside blocks are scoped to that block.

Answer 66

strict mode,