isPositive

The isPositive utility is a type guard that checks if a given number is strictly greater than zero.

Implementation

View Source Code

/**
 * Checks if the value is a positive number.
 *
 * @example
 * ```ts
 * isPositive(123); // true
 * isPositive(-123); // false
 * isPositive(0); // false
 * isPositive(0.1); // true
 * isPositive(-0.1); // false
 * isPositive('hello world'); // false
 * isPositive({}); // false
 * isPositive([]); // false
 * isPositive(new Date()); // false
 * isPositive(null); // false
 * isPositive(undefined); // false
 * isPositive(NaN); // false
 * ```
 *
 * @param arg - The argument to be checked.
 *
 * @returns `true` if the value is a positive number, else `false`.
 *
 */
export function isPositive(arg: unknown): arg is number {
  return typeof arg === 'number' && arg > 0;
}

Features

• Isomorphic: Works in both Browser and Node.js.
• Strict Check: Only returns true for values $> 0$ (zero is not considered positive).
• Type-safe: Properly typed for numeric inputs.

API

function isPositive(value: number): boolean;

Parameters

• value: The number to check.

Returns

• true if the number is greater than zero; otherwise, false.

Examples

Basic Usage

import { isPositive } from '@vielzeug/toolkit';

isPositive(10); // true
isPositive(0.1); // true
isPositive(0); // false
isPositive(-5); // false

Implementation Notes

• Returns true if value > 0.
• Throws nothing; returns false for non-numeric inputs if TypeScript checks are bypassed.

See Also

• isNegative: Check if a number is less than zero.
• isZero: Check if a number is exactly zero.
• isNumber: Check if a value is a number.