Foundation

Question 1

What does the console show: function foo() { return “bar”; } console.log( foo() );

Answer 1

bar

Question 2

How do you access the beta property value in this code? let foo = { alpha: 1, beta: 2 };

Answer 2

foo.beta

Question 3

What is the value of result?

let places = [{ city: ‘Amsterdam’, europe: true }, { city: ‘Paris’, europe: true }, { city: ‘Sacramento’, europe: false }];

let result = places[2].city;

Answer 3

Sacramento

Question 4

Which DOM function returns an element based on its id attribute?

Answer 4

document.getElementById( id );

Question 5

How many times will this loop execute?

let count = 5;

while (count) { console.log(count); count–; }

Answer 5

5

Question 6

What shows in the console?

var message = “no”;

function foo(message) {

message = “yes”;

}

foo( message );

console.log( message );

Answer 6

no

Question 7

T/F: A String is a iterable object

Answer 7

True. A String can be thought of as an array of characters

Question 8

What is the output of the following:

function stringToArray(){

let productNumber = “ABC-123”

let values = [… productNumber]

return values; }

Answer 8

[“A”,” B”, “C”, “-“, “1”,” 2”, “3”]

Question 9

What happens when you use spread operator to copy an object?

Answer 9

The new array is created, but the underlying objects are still the objects being referenced. So any operation performed on the copied array actually changes the referenced object.

Question 10

What are primitive types in JavaScript?

Answer 10

• Data that is NOT an object and has no methods
• Boolean
• Undefined
• Number
• BigInt
• String
• Symbol
• Null