Given an array arr of numbers, return the count of elements strictly less than 0.
Examples
Input: arr = [-1, 0, 1]
Output: 1
Input: arr = [-2, -5, -7]
Output: 3
Input: arr = [0, 2, 3]
Output: 0
Input: arr = []
Output: 0
Constraints
- Input must be an array of finite numbers
- Return false for non-array inputs
- Return false for arrays containing non-number values
- Return false for arrays containing NaN, Infinity, or -Infinity
Function Signature
function countNegatives(arr) {
// Your code here
}
Test Cases
- Base cases: empty array [], single negative [ -1 ], single non-negative [ 0 ]
- Mixed arrays: [ -1, 0, 1 ], [ -5, 2, -3, 4 ]
- All negatives: [ -1, -2, -3 ]
- No negatives: [ 0, 1, 2 ]
- Decimals: [ -1.5, -0.1, 0, 2.2 ]
- Invalid inputs: null, undefined, 42, '8', {}, () => {}, [1, 'a'], [NaN], [Infinity]
