isOdd
Determines if a number is odd with proper handling for negative numbers. Checks whether the given number is not divisible by 2. Uses appropriate modulo comparison based on the sign of the number to handle JavaScript's modulo behavior with negative numbers correctly.
Signature
const isOdd: (value: number) => boolean
Parameters
| Name | Type | Description |
|---|---|---|
value | - | Number to test for oddness |
Returns
True if the number is odd, false if even
Examples
Basic odd number detection
import { isOdd } from '@winglet/common-utils';
console.log(isOdd(1)); // true
console.log(isOdd(3)); // true
console.log(isOdd(5)); // true
console.log(isOdd(2)); // false
console.log(isOdd(4)); // false
console.log(isOdd(0)); // false (zero is even)
Negative numbers and edge cases
// Negative numbers (handled correctly)
console.log(isOdd(-1)); // true
console.log(isOdd(-3)); // true
console.log(isOdd(-5)); // true
console.log(isOdd(-2)); // false
console.log(isOdd(-4)); // false
// Large numbers
console.log(isOdd(999999)); // true
console.log(isOdd(1000001)); // true
Playground
import { isOdd } from '@winglet/common-utils'; console.log(isOdd(1)); // true console.log(isOdd(3)); // true console.log(isOdd(5)); // true console.log(isOdd(2)); // false console.log(isOdd(4)); // false console.log(isOdd(0)); // false (zero is even)
Notes
Implementation Details:
- Handles JavaScript's modulo behavior with negative numbers
- For positive numbers: checks if value % 2 === 1
- For negative numbers: checks if value % 2 === -1
- Zero is correctly identified as even (not odd)
Use Cases:
- Array filtering (odd indices, odd values)
- Alternating patterns complementary to even detection
- Mathematical algorithms requiring parity checks
- Game logic (turn-based systems, player identification)
- Data categorization and validation
- Optimization algorithms using odd/even properties
Performance: O(1) time and space complexity - single modulo operation with conditional check for sign handling.