add --strict option

[TheLartians]

Previously, the code was compiled without strict type-checking, meaning some undefined and null types could be lost in unions. Optimally compiler options would be taken from the tsconfig.json but I haven't found a reliable way to include it yet.

Example

export type T = number | undefined`

Before

T = float

After, using the --strict option

from typing_extensions import Union

T = Union[None,float]