Summary: Logic

Key points

• Booleans are primitive values that can only be true or false.
• All values have an inherent Boolean value of true or false.
• Truthy values are values that have a Boolean value of true. Most values are truthy.
• Falsy values have a Boolean value of false. The values that are falsy vary in different languages. There are nine falsy values in JavaScript.
• Negation makes truthy values false and falsy values true. Double negation returns a value’s Boolean value.
• Logical operators such as AND and OR can be used to combine multiple statements.
• Values can be compared to see if they’re equal, greater than, or less than other values.
• A conditional statement can be used to control the flow of a program based on a condition.
• The ternary operator is a concise way of writing an if–else statement in a single line of code.
• A switch statement can be used when there are multiple options.

After the quiz and challenge, we’ll move on to loops.