Modern JavaScript from the Beginning - Second Edition - Logical Operators

The video tutorial introduces logical operators, focusing on the AND and OR operators, and their practical applications. It explains how the AND operator requires all conditions to be true, while the OR operator needs only one true condition. The tutorial also covers the nullish coalescing operator, which returns the right operand if the left is null or undefined. Practical examples, including handling posts from a database, demonstrate these concepts in action.

What is the result of the expression '10 > 20 && 30 > 15'?

• true

• false

• undefined

• null

In the expression '10 && 20 && 0', what value is returned?

• 10

• 20

• undefined

• 0

How does the OR operator (||) determine the result of an expression?

• Returns the first falsy value

• Returns the last truthy value

• Returns the first truthy value

• Returns the last falsy value

What will the expression '0 || null || ""' return?

• null

• 0

• undefined

• ""

What does the nullish coalescing operator (??) return when the left operand is null?

• The left operand

• The right operand

• undefined

• null

Which operator would you use to return the right operand only if the left is null or undefined?

• ??

• ==

• ||

• &&

In the expression 'undefined ?? 20', what value is returned?

• 0

• null

• 20

• undefined