JavaScript Primitives, Variables, Objects, and Arrays

Question 1

What is the purpose of variables?

Answer 1

To store data that can be referenced later in your code

Question 2

How do you declare a variable?

Answer 2

var/let/const varName = data type

vet/let/const followed by varName followed by the assignment operator followed by the datatype

Question 3

How do you initialize (assign a value to) a variable?

Answer 3

var varName = varValue/Data

You use the assignment operator

Question 4

What characters are allowed in variable names?

Answer 4

Names can contain letters, digits, underscores, and dollar signs

Question 5

What does it mean to say that variable names are “case sensitive”?

Answer 5

To call the value of a variable, you must type the name exactly as you did when you declared the value to the name of the variable

camelCase

Question 6

What is the purpose of a string?

Answer 6

They are used to add new content into a page and they can contain markup

It’s a way to store data we can pass around

Question 7

What is the purpose of a number?

Answer 7

A number is used mainly for calculations

These store numeric values

Question 8

What is the purpose of a boolean?

Answer 8

They help determine which part of the script should run

True or False

Question 9

What does the = operator mean in JavaScript?

Answer 9

It is an assignment operator

It is saying you are going to assign a value to the variable

Question 10

What is the difference between null and undefined?

Answer 10

Undefined means it has an empty value

Null is an empty value but it was put there for a reason

Question 11

Why is it a good habit to include “labels” when you log values to the browser console?

Answer 11

It describes the variable or the value being logged

It is used for clarity - Labels help understand where and what the value is for

Question 12

Give five examples of JavaScript primitives.

Answer 12

Undefined, null, boolean, string, number

Question 13

What data type is returned by an arithmetic operation?

Answer 13

Arithmetic Operators are used for basic math

The data type returned would be number

Question 14

What is string concatenation?

Answer 14

String Concatenation is where you combine strings

‘Hello’ + ‘ ‘ + ‘World’ = Hello World

Two separate strings get glued together

Question 15

What data type is returned by comparing two values (, ===, etc?)

Answer 15

A boolean datatype is returned

True -or- False

Question 16

What does the += “plus-equals” operator do?

Answer 16

Additional Assignment

This adds the value of the right operand to a variable and assigns the result to the variable