floating-point.spec.ts

import { getDecimalPlaces, roundToMaxDecimalPlaces } from './index';

describe('floating point utils', () => {
  describe('getDecimalPlaces', () => {
    it('should calculate decimal places for a float', async () => {
      const n = getDecimalPlaces(5.001);
      expect(n).toBe(3);
    });

    it('should return no decimal places for a whole number', async () => {
      const n = getDecimalPlaces(5);
      expect(n).toBe(0);
    });

    it('should handle nullish values', () => {
      expect(getDecimalPlaces(undefined as any)).toBe(0);
      expect(getDecimalPlaces(null as any)).toBe(0);
      expect(getDecimalPlaces(NaN as any)).toBe(0);
    });
  });

  describe('roundToMaxDecimalPlaces', () => {
    it('should round to the highest number of places as references', async () => {
      const n = roundToMaxDecimalPlaces(5.12345, 1.12, 2.123);
      expect(n).toBe(5.123);
    });

    it('should handle nullish values', () => {
      expect(roundToMaxDecimalPlaces(undefined as any)).toBe(0);
      expect(roundToMaxDecimalPlaces(null as any)).toBe(0);
      expect(roundToMaxDecimalPlaces(NaN as any)).toBe(0);
    });
  });
});