JS Practice — Built-in Objects

setFullYear() — returns a number

📖 Usage Example

const d = new Date(2024, 0, 15)
d.setFullYear(2030)
d.getFullYear()  // → 2030

Use setFullYear() to mutate the year of a Date object in place; the month and day remain unchanged.

Date.prototype.setFullYear()

setFullYear() returns the new timestamp (ms since epoch) as a number.

Challenge: Verify that typeof d.setFullYear(2025) returns 'number'.

💡 Hints (1)

• setFullYear() returns the new numeric timestamp — useful for chaining arithmetic