if statement accepts an expression with a set of parentheses
else block is added to an
if block or series of
else if blocks. The
else block will be executed only if the
if condition fails.
! operator can be used to do one of the following:
false depending on the validity of the comparison. Comparison operators include:
The strict equality operator (
===) checks if two values are the same and returns
true if they are the same. The inequality comparison operator (
!==) check if two values are different and return
true if they aren’t the same.
else if Statement
After an initial
else if blocks can each check an additional condition. An optional
else block can be added after the
else if block(s) to run by default if none of the conditionals evaluated to truthy.
The logical AND operator
&& checks two values and returns a boolean. If both values are truthy, then it returns
true. If one, or both, of the values is falsy, then it returns
The logical OR operator
|| checks two values and returns a boolean. If one or both values are truthy, it returns
true. If both values are falsy, it returns
switch statements provide a means of checking an expression against multiple values. It first evaluates an expression. The result of the expression is matched against values in one or more
case clauses. If a case matches, the code inside that clause is executed.
case clause should finish with a
break keyword. If no case matches but a
default clause is included, the code inside
default will be executed. If
break is omitted from the block of a
case (or the execution is not broken otherwise, such as returning from a function with a switch), the
switch statement will continue to check against
case values until a break is encountered or the flow is broken.
The ternary operator allows for a compact syntax in the case of binary (choosing between two choices) decisions. It accepts a condition followed by a
? operator, and then two expressions separated by a
:. If the condition evaluates to truthy, the first expression is executed, otherwise, the second expression is executed. It can be read as “IF condition THEN expression1 ELSE expression2”.