Basics
JS Booleans
JavaScript Boolean Values
JavaScript booleans handle true/false, with truthy/falsy evaluations.
What are Booleans?
In JavaScript, a boolean represents one of two values: true or false. Booleans are commonly used in control structures such as if statements and loops to determine the flow of a program based on conditions.
Boolean Values in JavaScript
The boolean data type has two literal values: true and false. These values are case-sensitive and must be written in lowercase.
Truthy and Falsy Values
In JavaScript, a value that is not a boolean can still behave like a boolean in conditional contexts, such as if statements. These values are classified as either truthy or falsy:
- Truthy values are treated as
truein logical expressions. - Falsy values are treated as
falsein logical expressions.
JavaScript considers the following values as falsy:
false0""(empty string)nullundefinedNaN(Not-a-Number)
Everything else is considered truthy.
Boolean Operations
JavaScript provides several operations that work with boolean values, including logical operators such as && (AND), || (OR), and ! (NOT).
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