Up and Going

Question 1

Javascript is to Java as

Answer 1

Carnival is to Car

Question 2

Javascript gets its procedural roots from

Answer 2

C and a little Scheme/Lisp style functional roots

Question 3

Definition of computer language

Answer 3

Rules for valid format and combinations of instructions ( aka syntax)

Question 4

Code def

Answer 4

Set of special instructions to tell code what to do

Question 5

Statement def

Answer 5

Group of words, numbers and operators to perform a specific task

Question 6

Expression def

Answer 6

any reference to a variable or value

Question 7

Call expression

Answer 7

A function

Question 8

Interpreter or compiler def

Answer 8

A special utility on a computer that translates codes into commands

Question 9

Interpretted vs compiled

Answer 9

Interpreted runs line by line. Compiled translates ahead of time and runs later

Question 10

How does Javascript interpret/compile?

Answer 10

Compiles on the fly and runs the compiled code

Question 11

+= -= are known as

Answer 11

Compound assignment. Combines a math operation with an assignment

Question 12

== is called

Answer 12

loose equals

Question 13

=== is called

Answer 13

strict equals

Question 14

Basic types like boolean and string are refered to as

Answer 14

Primitive types

Question 15

Conversion between value types is called

Answer 15

Coercion

Question 16

To convert “42” to 42

Answer 16

Number(“42”)

Question 17

Comments should explain

Answer 17

Why not what

Question 18

Static typing is AKA

Answer 18

type enforcement

Question 19

Strong typing

Answer 19

Variable type cannot change (like string to integer)

Question 20

Weak typing

Answer 20

Variable type can change

Question 21

Weak typing is AKA

Answer 21

dynamic typing

Question 22

Primary purpose of variables

Answer 22

To manage program state

Question 23

To make variable foo 245.654 to 2 decimal places

Answer 23

foo.toFixed(2)

Question 24

Block def

Answer 24

A series of statements put together

Question 25

Falsey def

Answer 25

Anything that is false in a boolean

Question 26

Technical term for scope

Answer 26

Lexical scope

Question 27

Scope def

Answer 27

Collection of variables and rules for variables accessible by name

Question 28

To find type of foo

Answer 28

typeof foo

Question 29

typeof returns which possible types (7 as of ES6)

Answer 29

``` undefined string number boolean object function ```

Question 30

Why is typeof null an object?

Answer 30

Long standing bug with too much legacy to change

Question 31

obj["a"] style and obj.a style names

Answer 31

bracket notation and dot notation

Question 32

to make uppercase

Answer 32

sting.toUpperCase()

Question 33

Explicit coercion

Answer 33

You can see in code a type conversion Example: a = "42" a = Number(a)

Question 34

To convert string to number

Answer 34

Number("12")

Question 35

Implicit Conversion

Answer 35

``` Cannot see the coercion in code Example: a = "43" a = a + 1 a === 44 ```

Question 36

Falsy values in JS

Answer 36

``` "" 0 null undefined false ```

Question 37

Difference between == and ===

Answer 37

``` == checks for value with coercion allowed === checks for value and type ```

Question 38

A non-number string and a number with a comparison operator will always return eg "a" > 3

Answer 38

False

Question 39

What are reserved words?

Answer 39

names that variables cannot have such as true or for

Question 40

Hoisting def

Answer 40

When a variable is declared to belong to the entire scope

Question 41

Why add a break to switch statements?

Answer 41

Cases will run with any matches. It's not like if statements

Question 42

The one line if statement is known as the

Answer 42

"conditional operator" or "ternary operator"

Question 43

IIFE sf

Answer 43

Immediately Invoked Function Expressions

Question 44

What is a polyfill?

Answer 44

a new feature and producing a piece of code that's equivalent to the behavior but is able to run in older JS environments

Question 45

Transpiling def

Answer 45

tool that converts your newer code into older code equivalents

Question 46

3 reasons to use new syntax even though it is transpiled (by things like babel)

Answer 46

Easier to read Easier to maintain Optimized for new browsers

Question 47

What is document in document.getElementBy

Answer 47

Global variable for browser code. It's a special object often called a Host Object

Question 48

About the getElementById()

Answer 48

Not a normal JS function. It is an enterface built into the DOM from the browser

Question 49

Treaditionally the DOM and it's objects were written in

Answer 49

C/C++

Question 50

Closure def

Answer 50

A way to remember and access a function's scope

Question 51

What is the authors criticism of JS developers?

Answer 51

Serious developers in other languages put huge effort into learning the language whereas JS developers get content with their minimal amount

Question 52

Generators are

Answer 52

pausing yielding points in JS functions to be resumed asynchronously later