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subtract ​

Subtracts one number from another with precision handling for financial calculations. Supports both regular numbers and bigint for exact precision.

Implementation ​

View Source Code
ts
/**
 * Subtracts one number from another with precision handling for financial calculations.
 * Supports both regular numbers and bigint for exact precision.
 *
 * @example
 * ```ts
 * subtract(20, 10); // 10
 * subtract(0.3, 0.1); // 0.2 (precision-safe)
 * subtract(300n, 100n); // 200n
 * ```
 *
 * @param a - Number to subtract from
 * @param b - Number to subtract
 * @returns Difference of a and b
 */
export function subtract(a: number, b: number): number;
export function subtract(a: bigint, b: bigint): bigint;
export function subtract(a: number | bigint, b: number | bigint): number | bigint {
  if (typeof a === 'bigint' && typeof b === 'bigint') {
    return a - b;
  }
  if (typeof a === 'number' && typeof b === 'number') {
    return a - b;
  }
  throw new TypeError('Both arguments must be of the same type (number or bigint)');
}

Features ​

  • Type-Safe: Separate overloads for number and bigint
  • Precision: Works with bigint for financial calculations
  • Error Handling: Prevents mixing number and bigint types
  • Isomorphic: Works in both Browser and Node.js

API ​

ts
function subtract(a: number, b: number): number;
function subtract(a: bigint, b: bigint): bigint;

Parameters ​

  • a: Number to subtract from (minuend)
  • b: Number to subtract (subtrahend)

Returns ​

  • Difference of a minus b (same type as input)

Examples ​

Basic Number Subtraction ​

ts
import { subtract } from '@vielzeug/toolkit';

subtract(20, 10); // 10
subtract(100, 30); // 70
subtract(0.3, 0.1); // 0.2 (precision-safe)

Negative Results ​

ts
import { subtract } from '@vielzeug/toolkit';

subtract(10, 20); // -10
subtract(5, 15); // -10

BigInt for Financial Precision ​

ts
import { subtract } from '@vielzeug/toolkit';

// Working with cents
const total = 100000n; // $1,000.00
const discount = 15000n; // $150.00

subtract(total, discount); // 85000n ($850.00)

Real-World Example: Refund Calculation ​

ts
import { subtract } from '@vielzeug/toolkit';

const orderTotal = 45999n; // $459.99
const refundAmount = 12500n; // $125.00

const remaining = subtract(orderTotal, refundAmount);
// 33499n ($334.99)

Calculate Change ​

ts
import { subtract } from '@vielzeug/toolkit';

const amountPaid = 10000n; // $100.00
const price = 8795n; // $87.95

const change = subtract(amountPaid, price);
// 1205n ($12.05)

Implementation Notes ​

  • Both parameters must be the same type (number or bigint)
  • Throws TypeError if you try to mix number and bigint
  • For financial calculations, use bigint to store amounts in minor units (cents)
  • Handles negative results correctly
  • Can result in negative numbers when subtracting larger value from smaller

See Also ​