Number.toFixed but without rounding the numbers

toFixedWithoutRounding.test.ts

describe('toFixedWithoutRounding()', () => {
  it('should return a string', () => {
    const result = toFixedWithoutRounding(3271.24);
    expect(typeof result).toBe('string');
  });

  it('should return expected numbers', () => {
    expect(toFixedWithoutRounding(7933.2982426892, 1)).toBe('7933.2');
    expect(toFixedWithoutRounding(7933.2982426892, 2)).toBe('7933.29');
    expect(toFixedWithoutRounding(7933.2982426892, 3)).toBe('7933.298');

    expect(toFixedWithoutRounding(103415.324)).toBe('103415.32');
    expect(toFixedWithoutRounding(103415.324, 3)).toBe('103415.324');
    expect(toFixedWithoutRounding(103415.324, 4)).toBe('103415.3240');

    expect(toFixedWithoutRounding(0.893, 3)).toBe('0.893');
    expect(toFixedWithoutRounding(0.893, 4)).toBe('0.8930');
    expect(toFixedWithoutRounding(0.893, 5)).toBe('0.89300');
  });
});

toFixedWithoutRounding.ts

export function toFixedWithoutRounding(value: number, decimals = 2): string {
  const [number, numberDecimals = ''] = (value ?? 0).toString().split('.');

  const truncatedDecimals = numberDecimals.slice(0, decimals);
  const formattedDecimals = truncatedDecimals.padEnd(decimals, '0');
  const fixedNumber = [number, formattedDecimals].join('.');

  return fixedNumber;
}