Type guard based on exclude
$ npm install @younho9/notimport not from '@younho9/not';
const isNullable = (value: unknown): value is null | undefined =>
value === null || value === undefined;
const isNonNullable = not(isNullable);
declare const someValue: string | null | undefined;
if (isNonNullable(someValue)) {
someValue;
//=> string
}