if digits < 0:
    echo "B:"
    digits = digits * -1
    newSize = parseFloat(originalSize) / (pow(1000.0, digits))
    echo newSize
    let newSizeString = fmt"{newSize:f}"
    echo newSizeString
    result = &"{newSizeString} {toUnit.toUpper()}"

Output:

B:
1.024e-12
0.000000