JavaScript Basics

Question 1

What is JavaScript?

Answer 1

JavaScript is a powerful, flexible, and fast programming language used for interactive web development

Question 2

Define the Console.

Answer 2

The console is a panel that displays important messages, like errors, for developers.

If we want to see things appear on our screen, we can print, or log, to our console directly.

Keywords are words that are built into the JavaScript language, so the computer will recognize them and treats them specially.

Question 3

What is the purpose of a semi-colon in a line of code?

Answer 3

The semicolon denotes the end of the line, or statement.

Question 4

Define a comment.

Answer 4

Comments can explain what the code is doing, leave instructions for developers using the code, or add any other useful annotations.

These comments exist just for human readers.

Question 5

2 types of comment?

Answer 5

A single line comment will comment out a single line and is denoted with two forward slashes // preceding it.

A multi-line comment will comment out multiple lines and is denoted with /* to begin the comment, and */ to end the comment.

Question 6

Name the 6 primitive data types.

Answer 6

Number
String
Boolean
Null
Undefined
Symbol

Question 7

Define a data type.

Answer 7

Data types are the classifications we give to the different kinds of data that we use in programming.

There are 7 fundamental types

Question 8

What does the “string” datatype involve?

Answer 8

String: Any grouping of characters on your keyboard (letters, numbers, spaces, symbols, etc.) surrounded by single quotes: ‘ … ‘ or double quotes “ … “

Question 9

What does the “Boolean” datatype involve?

Answer 9

Boolean: This data type only has two possible values— either true or false

Question 10

What is the Null datatype?

Answer 10

This data type represents the intentional absence of a value, and is represented by the keyword null

Question 11

What is the Undefined datatype?

Answer 11

This data type is denoted by the keyword undefined and represents an intentional absence

Question 12

What is the Symbol datatype?

Answer 12

Symbol: A newer feature to the language, symbols are unique identifiers, useful in more complex coding.

Question 13

What is the Object datatype?

Answer 13

Object: Collections of related data.

Question 14

Define an operator?

Answer 14

An operator is a character that performs a task in our code.

Question 15

What is an arithmetic operator?

Answer 15

Built-in arithmetic operators allow us to perform mathematical calculations on numbers.

Question 16

Name 5 arithmetic operators.

Answer 16

Add: +
Subtract: -
Multiply: *
Divide: /
Remainder: %

Question 17

What is String Concatenation?

Answer 17

The process of appending one string to another. When a + operator is used on two strings, it appends the right string to the left string:

Question 18

Define a Method.

Answer 18

Methods are actions we can perform. JavaScript provides a number of string methods.

We call, or use, these methods by appending an instance with:

a period (the dot operator)
the name of the method
opening and closing parentheses

e.g. .startsWith()

Question 19

What does the Number datatype categorise?

Answer 19

Numbers are any number without quotes

Question 20

What is the dot operator?

Answer 20

We can access properties and methods by using the ., dot operator.

Question 21

What does the “Var” keyword do?

Answer 21

Short for variable, is a JavaScript keyword that creates, or declares, a new variable.

Question 22

What is camel casing?????????????

Answer 22

Camel casing is when you bunch words up together to form a string of code.

The first word is lowercase, the following is Capitalized

e.g. .startsWith()
.myName()

Question 23

Example of an assignment operator.

Answer 23

=

Question 24

What does the “Let” value do?

Answer 24

The let keyword signals that the variable can be reassigned a different value.

Question 25

What does the “Const” variable do?

Answer 25

A const variable cannot be reassigned because it is constant. If you try to reassign a const variable, you’ll get a TypeError.

Question 26

What does the increment operator do?

Answer 26

The increment operator will increase the value of the variable by 1. ++

Question 27

What does the decrement operator do?

Answer 27

The decrement operator will decrease the value of the variable by 1. –

Question 28

What is a variable?

Answer 28

Variables hold reusable data in a program and associate it with a name. Variables are stored in memory.

Question 29

What are Conditional Statements?

Answer 29

A conditional statement checks a specific condition(s) and performs a task based on the condition(s).

Question 30

What does the “if” conditional statement do?

Answer 30

It will perform an action based on whether a statement is true.

Question 31

What does the “else” conditional statement do?

Answer 31

It will perform an action based on whether a statement is false, as an alternative action.

Question 32

What are comparison operators?

Answer 32

Different types of operators used to compare values.

Comparison operators compare the value on the left with the value on the right. For instance:

10 < 12 // Evaluates to true

Question 33

Name 3 logical operators.

Answer 33

And (&&), or (||), not ( ! )