compare-shield/dist/compare.js

A coercion-free numeric comparison utility for <, <=, >, >= within JavaScript's safe integer range.

// Constant for valid operators
const VALID_OPERATORS = ["<", "<=", ">", ">="];
/**
 * Executes a strict numeric comparison without implicit type conversion.
 * Ensures that both operands are valid finite numbers.
 * Returns false for invalid inputs, unsupported operators, or special numeric values.
 *
 * @param a - First operand to compare
 * @param operator - Comparison operator: '<', '<=', '>', '>='
 * @param b - Second operand to compare
 * @returns True if both operands are valid and the comparison succeeds; false otherwise
 *
 * @example
 * import { compare } from 'compare-shield';
 *
 * compare(5, '<', 10); // true
 * compare(3.14, '<=', 3.14); // true
 * compare(null, '<', 5); // false
 * compare(NaN, '>=', 0); // false
 * compare(Infinity, '<', 1000); // false
 */
export function compare(a, operator, b) {
    const isValidOperator = VALID_OPERATORS.includes(operator);
    // Check operator validity
    if (!isValidOperator) {
        return false;
    }
    // Extract validation checks to variables
    const isANullish = a === null || a === undefined;
    const isBNullish = b === null || b === undefined;
    // Check for null/undefined
    if (isANullish || isBNullish) {
        return false;
    }
    const isANumber = typeof a === "number";
    const isBNumber = typeof b === "number";
    const isAFinite = isANumber && Number.isFinite(a);
    const isBFinite = isBNumber && Number.isFinite(b);
    const isASafeInteger = Number.isSafeInteger(a);
    const isBSafeInteger = Number.isSafeInteger(b);
    // Check types, finite values and if values are safe to perform comparison on
    if (!isANumber ||
        !isBNumber ||
        !isAFinite ||
        !isBFinite ||
        !isASafeInteger ||
        !isBSafeInteger) {
        return false;
    }
    // Perform the comparison
    switch (operator) {
        case "<": {
            return a < b;
        }
        case "<=": {
            return a <= b;
        }
        case ">": {
            return a > b;
        }
        case ">=": {
            return a >= b;
        }
        default: {
            return false;
        }
    }
}
export default compare;