Conditionals

Question 1

What is control flow?

Answer 1

The order in which statements are executed in a program.

Control structures such as conditionals (if statements and the like) alter control flow by only executing blocks of code if certain conditions are met.

Question 2

OR || operator

Answer 2

Checks two values and returns a boolean.
*if one or both values are truthy = true
*if both values are falsy = false

Question 3

AND && operator

Answer 3

Checks two values and returns a boolean
*if both values are truthy = true
*if one or both values are falsy = false

Question 4

Ternary Operator

Answer 4

Allows for a compact syntax in the case of binary
It accepts a condition followed by ?, then two expressions separated by :

If the condition is truthy, the first expression is executed
If the condition is falsy, the second expression is executed

let price = 10.5;
let day = “Monday”;

day === “Monday” ? price -= 1.5 : price += 1.5;

Question 5

if statement

Answer 5

Accepts an expression with a set of parentheses
*if the expression is truthy, the code executes
* if the expression is falsy, the code will not execute

Question 6

else statement

Answer 6

Can be added to an if block or statement, and will be evaluated only if the if condition is falsy

Question 7

switch statement

Answer 7

Checks an expression against multiple case clauses. If a case matches, the code inside that clause is executed.

The case clause should finish with a break keyword. If no case matches but a default clause is included, the code inside the default will be executed.

Question 8

Not ! operator

Answer 8

Can be used to invert a boolean value or invert the truthiness of non-boolean values

let lateToWork = true;
let oppositeValue = !lateToWork; //false

Question 9

Comparison Operators

Answer 9

=== strict equal
!== strict not equal
> greater than
>= greater than or equal
< less than
<= less than or equal

Question 10

Truthy and Falsy Values

Answer 10

Values that are evaluated to true are known as truthy
Values that are evaluated to false are known as falsy

Falsy values include:
false
0
empty strings
null
undefined
NaN.

All other values are truthy.