JS Practice — Built-in Objects

valueOf() — Boolean valueOf

📖 Usage Example

// Retrieve the primitive value of an object
const n = new Number(42)
n.valueOf()   // → 42
const obj = { valueOf() { return 10 } }
obj + 5       // → 15

Use valueOf() to retrieve the underlying primitive value of an object; JavaScript calls it automatically in numeric contexts.

valueOf() — Boolean

Boolean wrapper objects have a valueOf() that returns the wrapped primitive boolean value.

Challenge: Verify that Boolean's valueOf returns a boolean primitive.

💡 Hints (1)

• Boolean wrapper objects are always truthy; use valueOf to get the primitive