Examples
Example 1
Input: n = 0
Output: 1
- Explanation: 0! = 1 by definition.
Example 2
Input: n = 4
Output: 24
- Explanation: 4! = 4 × 3 × 2 × 1 = 24
Example 3
Input: n = 6
Output: 720
- Explanation: 6! = 6 × 5 × 4 × 3 × 2 × 1
Constraints
- n must be a non-negative integer
- Large values of n may cause recursion depth issues
- Return false for negative numbers
- Return false for non-integers
- Return false for non-numeric values (NaN, strings, arrays, objects, null, undefined)
Function Signature
function factorial(n) { }
Test Cases
n Expected Output
0 1
1 1
3 6
5 120
7 5040
10 3628800
Invalid inputs → false Examples:
- factorial(-1)
- factorial(2.5)
- factorial("5")
- factorial({})
- factorial([])
- factorial(null)
- factorial(undefined)
