The code will return 'default'. This demonstrates the logical OR (||) operator's behavior with truthy and falsy values. Since 0 is falsy, the expression 0 || 'default' evaluates to 'default'. The logical OR returns the first truthy operand it encounters, or the last operand if all are falsy. This pattern is commonly used for setting default values in JavaScript, especially before the introduction of the nullish coalescing operator (??). However, it's important to be aware that this will replace all falsy values (not just null or undefined), which might not always be desirable if 0 or '' are valid values in your context.