Javascript Functions Basics

Question 1

When is the first expression in the parentheses for a for loop (known as the initialization) evaluated?

Answer 1

Executed ONLY 1x before loop starts

it’s only job is to set the variable for the loop start

Question 2

When is the second expression in the parentheses for a for loop (known as the condition) evaluated?

Answer 2

Runs before each iteration

Defines the condition of the initial variable for loop to run.

Tells us when to stop when to stop

Question 3

When is the third / final expression in the parentheses for a for loop evaluated?

Answer 3

Statement 3 is executed (every time) after the code block has been executed

& before the conditional expression

Question 4

What is the purpose of the condition (stmt 2) in a for loop?

Answer 4

statement 2 is used to evaluate the condition of the initial variable.

If statement 2 returns true, the loop will start over again, if it returns false, the loop will end.

Question 5

What is the purpose of the final expression in a for loop?

Answer 5

Increment or manipulate the value of initial variable until it is stopped by the condition

Question 6

What does strictly equal mean?

Answer 6

===

checks whether two operands are EQUAL and returns BOOLEAN RESULT

Question 7

What is the logical and operator?

Answer 7

&&

conjuncts 2 set of boolean operands.
returns result of TRUE only if all operands are true; otherwise returns result of FALSE

Question 8

logical operators

Answer 8

&& and
|| or
! not (purpose is to flip the boolean)

Question 9

Can you name some comparison operators?

Answer 9

== equal to
=== equal to & equal type
!= not equal
!== not equal nor equal type
><
>=
<=

Question 10

What are the five parts of a function definition?

Answer 10

1. function keyword
2. function name - opt.
3. parameter lists (in parentheses in initial fxn def; serve as PLACEHOLDER for real values)
4. code block / body of fxn;
   in curly braces
5. return statement - (what should pop out of fxn when it is called and be assigned to variable) - opt.

Question 11

How do you call a function?

Answer 11

functionName( argument(s) );

**no code block in { }

Question 12

parameter vs argument

Answer 12

parameter in initial fxn declaration
it’s a local variable stored in the function
(SCOPE: can only be access from inside, not outside the fxn) (car window reflective - can look out but not in)

argument when fxn is called

Question 13

Return

Answer 13

causes fxn to produce value when called

prevents the rest of code block from running (EXITS FUNCTION)

Question 14

what is a function in JS?

Answer 14

fucntion is a set of code that we can use anytime by calling it

Question 15

purpose of a loop

Answer 15

do something as fast as possible

like an assembly line

Question 16

What does “iteration” mean in the context of loops?

Answer 16

each time loop runs until condition is false

Question 17

When does the condition expression of a while loop get evaluated?

Answer 17

before code block executes even if condition is false

Question 18

for loop details (in debugger)

Answer 18

work
expression
final condition

Question 19

Besides a return statement, which exits its entire function block, which keyword exits a loop before its condition expression evaluates to false?

Answer 19

break

Question 20

How do you iterate through the keys of an object?

Answer 20

the “for…in” loop

for (var key in object)

Question 21

how to choose which loop?

Answer 21

for. .. in = properties/keys
for. .. of = values

while loop = when you don’t know how long / how many times something has to be done
(ex/ drink until no longer thirst, no idea how long thirst is)

for loop = when you know # of times you need to iterate