import { parseStringNumber } from "./utils";
/**
* Compares two numbers represented as strings
* @param a First number as string
* @param b Second number as string
* @returns 1 if a > b, -1 if a < b, 0 if a == b
*/
export default function compare(a: string, b: string): number {
// Handle empty or invalid inputs
if (a === undefined || a === null || b === undefined || b === null) {
throw new Error("Invalid input: both numbers must be provided");
}
// Parse both numbers
const numA = parseStringNumber(a);
const numB = parseStringNumber(b);
// Handle sign comparison first
if (numA.sign !== numB.sign) {
return numA.sign > numB.sign ? 1 : -1;
}
// Both numbers have the same sign, compare absolute values
const absCompare = compareAbsoluteValues(numA, numB);
// If both negative, invert the result
const result = numA.sign === -1 ? -absCompare : absCompare;
// Ensure we return 0 instead of -0
return result === 0 ? 0 : result;
}
/**
* Compares absolute values of two parsed numbers
* @param a Parsed number A
* @param b Parsed number B
* @returns 1 if |a| > |b|, -1 if |a| < |b|, 0 if |a| == |b|
*/
function compareAbsoluteValues(a: any, b: any): number {
// Compare integer part lengths first
const intLenA = a.integerPart.length;
const intLenB = b.integerPart.length;
if (intLenA > intLenB) return 1;
if (intLenA < intLenB) return -1;
// Integer parts have same length, compare digit by digit
for (let i = 0; i < intLenA; i++) {
const digitA = a.integerPart[i];
const digitB = b.integerPart[i];
if (digitA > digitB) return 1;
if (digitA < digitB) return -1;
}
// Integer parts are equal, compare fractional parts
const maxFracLen = a.fractionalPart.length > b.fractionalPart.length
? a.fractionalPart.length
: b.fractionalPart.length;
for (let i = 0; i < maxFracLen; i++) {
const digitA = i < a.fractionalPart.length ? a.fractionalPart[i] : "0";
const digitB = i < b.fractionalPart.length ? b.fractionalPart[i] : "0";
if (digitA > digitB) return 1;
if (digitA < digitB) return -1;
}
// Numbers are equal
return 0;
}
/**
* Checks if two numbers are equal
* @param a First number as string
* @param b Second number as string
* @returns true if a == b, false otherwise
*/
export function isEqual(a: string, b: string): boolean {
return compare(a, b) === 0;
}
/**
* Checks if first number is greater than second
* @param a First number as string
* @param b Second number as string
* @returns true if a > b, false otherwise
*/
export function isGreaterThan(a: string, b: string): boolean {
return compare(a, b) === 1;
}
/**
* Checks if first number is less than second
* @param a First number as string
* @param b Second number as string
* @returns true if a < b, false otherwise
*/
export function isLessThan(a: string, b: string): boolean {
return compare(a, b) === -1;
}
/**
* Finds the minimum of two or more numbers
* @param a First number as string
* @param b Second number as string
* @param rest Additional numbers
* @returns The smallest number as string
*/
export function min(a: string, b: string, ...rest: string[]): string {
let minimum = compare(a, b) <= 0 ? a : b;
for (const num of rest) {
if (compare(num, minimum) < 0) {
minimum = num;
}
}
return minimum;
}
/**
* Finds the maximum of two or more numbers
* @param a First number as string
* @param b Second number as string
* @param rest Additional numbers
* @returns The largest number as string
*/
export function max(a: string, b: string, ...rest: string[]): string {
let maximum = compare(a, b) >= 0 ? a : b;
for (const num of rest) {
if (compare(num, maximum) > 0) {
maximum = num;
}
}
return maximum;
}