Type fix

src/either/either.test.ts

@@ -173,7 +173,7 @@ describe('Either', () => {
 
 		describe('mapLeft', () => {
 			it('supports right return', () => {
-				const newAdt = right(999)
+				const newAdt = right<Error, number>(999)
 
 				const actual = adt.mapLeft(() => newAdt)
 

src/either/either.ts

@@ -25,6 +25,7 @@ const createRight = <E, A>(data: A) =>
 			),
 		fold: <B>(_: (left: E) => B, ifRight: (right: A) => B) => ifRight(data),
 		getOrElse: () => data,
+		// map: (ifRight) => rightOf<E, any>(ifRight(data)),
 		flatMap: (ifRight) => rightOf<E, any>(ifRight(data)),
 		mapLeft: () => rightOf(data),
 	})
@@ -42,6 +43,7 @@ const createLeft = <E, A>(data: E) => {
 			),
 		fold,
 		getOrElse: fold,
+		// map: () => leftOf(data),
 		flatMap: () => leftOf(data),
 		mapLeft: (ifLeft) => leftOf<any, A>(ifLeft(data)),
 	})
@@ -51,6 +53,10 @@ export const rightOf = <E, A>(data: A): Either<E, A> => (isEither<E, A>(data) ?
 
 export const leftOf = <E, A>(data: E): Either<E, A> => (isEither<E, A>(data) ? data : createLeft(data))
 
-export const right = createRight
+export const right = <E = [Error, 'Specify Left type in right()'], A = [Error, 'Specify Right type in right()']>(
+	data: A
+) => createRight<E, A>(data)
 
-export const left = createLeft
+export const left = <E = [Error, 'Specify Left type in left()'], A = [Error, 'Specify Right type in left()']>(
+	data: E
+) => createLeft<E, A>(data)

src/types.ts

@@ -10,10 +10,14 @@ interface EQ<E, A> {
 	equals(value: Either<E, A>): boolean
 }
 
+// type AnyNonEither = Exclude<any, Either<any, any>>
+
 interface Chainable<E, A> {
-	flatMap<B>(ifRight: (right: A) => Either<E, B>): Either<E, B>
+	// map<B extends AnyNonEither = A>(ifRight: (right: A) => B): Either<E, B>
+
+	flatMap<B = A>(ifRight: (right: A) => Left<E, A> | Right<E, B>): Either<E, B>
 
-	mapLeft<G>(ifLeft: (left: E) => Either<G, A>): Either<G, A>
+	mapLeft<G = E>(ifLeft: (left: E) => Left<G, A> | Right<E, A>): Either<G, A>
 }
 
 interface Foldable<E, A> {