fix: allow null types in constructor and maybe() (#175)

BREAKING CHANGE: allow null types in constructor and maybe()

Author: patrickmichalina

src/maybe/maybe.factory.ts

@@ -1,7 +1,7 @@
 import { Maybe } from './maybe'
 import { IMaybe } from './maybe.interface'
 
-export function maybe<T>(value?: T): Maybe<T> {
+export function maybe<T>(value?: T | null): Maybe<T> {
   return new Maybe<T>(value)
 }
 

src/maybe/maybe.spec.ts

@@ -66,14 +66,14 @@ describe('Maybe', () => {
     })
 
     it('should handle "some" case when input is null', () => {
-      const sut = null as string | undefined | null
-      const maybeAString = maybe(sut).valueOr('default output')
+      const sut: string | null = null
+      const maybeAString = maybe<string>(sut).valueOr('default output')
 
       expect(maybeAString).toEqual('default output')
     })
 
     it('should handle "some" case when input is ""', () => {
-      const sut = '' as string | undefined | null
+      const sut: string | undefined | null = ''
       const maybeAString = maybe(sut).valueOr('fallback')
 
       expect(maybeAString).toEqual('')

src/maybe/maybe.ts

@@ -2,7 +2,7 @@ import { IMaybePattern, IMaybe } from './maybe.interface'
 
 export class Maybe<T> implements IMaybe<T>  {
 
-  constructor(private readonly value?: T) { }
+  constructor(private readonly value?: T | null) { }
 
   public of(value: T): IMaybe<T> {
     return new Maybe<T>(value)