JS Basics

Question 1

What are the primitive data types?

Answer 1

Numbers, Strings, Boolean Values

Question 2

What are the composite data types?

Answer 2

Objects, Functions, Arrays, JavaScript Object Literals

Question 3

What is a data type?

Answer 3

A general term to describe categories of values that a program or programming language can make use of.

Question 4

What is the Number Data Type?

Answer 4

A numeric value

Question 5

What is the String Data Type?

Answer 5

A sequence of valid characters usually used for text surrounded by quotes.

Question 6

What is the Boolean Data Type?

Answer 6

A true or false value.

Question 7

What is a switch statement?

Answer 7

Allows you to set a number of options (cases) and check an expression to see if it matches any of them. If no match is found it returns the default action.

Question 8

What does && do?

Answer 8

AND, Returns true if both conditions are true.

Question 9

What does || do?

Answer 9

OR, Returns true if one or both of the conditions are true.

Question 10

What is a heterogeneous array?

Answer 10

An array with mixed data types.

Question 11

What is a jagged array?

Answer 11

Jagged arrays are when you have 2 dimensional arrays of varying length

Question 12

What is a 2 dimensional/multidimensional array?

Answer 12

An array that has an array inside of it

Question 13

What type of object syntax is: var obj = { } ?

Answer 13

Object Literal Syntax

Question 14

What type of object syntax is: var obj = new Object( ); ?

Answer 14

Object Constructor Syntax

Question 15

What is a property?

Answer 15

A variable associated with an object

Question 16

What is a method?

Answer 16

A function (action) associated with an object

Question 17

What does myObj.hasOwnProperty(“name”); do?

Answer 17

Checks to see if the object myObj has a property called name and returns true if it does.

Question 18

What does for(var myProp in places){} do?

Answer 18

Runs the code for all properties in the object places all at once.

Question 19

What does for(var x in blank) {
console.log(blank[x]);
} do?

Answer 19

It will print all the property values for the object blank.

Question 20

What is a ternary operator?

Answer 20

A ternary operator is often used as a shortcut for the if statement.

Question 21

What is the syntax of the ternary operator?

Answer 21

condition ? expression1 : expression2

Question 22

What does the ? and : stand for in a ternary operator?

Answer 22

the ? creates the condition followed by the expression to run if the condition is true. The : creates the second condition to run if it’s false (else{})

Question 23

What is a function?

Answer 23

A body of code that can be called by other code or by itself, or a variable that refers to the function. (a verb in programming).

When a function is called, arguments are passed to the function as input, and the function can optionally return an output. A function is also an object.