Added Either and Option type extractors (#2255)

Author: jessekelly881

.changeset/odd-bikes-flow.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+added Either.Either.{Left,Right} and Option.Option.Value type utils

packages/effect/dtslint/Either.ts

@@ -165,3 +165,9 @@ pipe(
     _s: string
   ) => "b" as const)
 )
+
+// $ExpectType number
+export type R = Either.Either.Right<typeof string$number>
+
+// $ExpectType string
+export type L = Either.Either.Left<typeof string$number>

packages/effect/dtslint/Option.ts

@@ -195,3 +195,6 @@ numberOrString.pipe(Option.andThen(numberOrString))
 
 // $ExpectType Option<string | number>
 numberOrString.pipe(Option.andThen(() => numberOrString))
+
+// $ExpectType string | number
+export type V = Option.Option.Value<typeof numberOrString>

packages/effect/src/Either.ts

@@ -90,6 +90,22 @@ export interface EitherTypeLambda extends TypeLambda {
   readonly type: Either<this["Target"], this["Out1"]>
 }
 
+/**
+ * @since 2.0.0
+ */
+export declare namespace Either {
+  /**
+   * @since 2.0.0
+   * @category type-level
+   */
+  export type Left<T extends Either<any, any>> = [T] extends [Either<infer _A, infer _E>] ? _E : never
+  /**
+   * @since 2.0.0
+   * @category type-level
+   */
+  export type Right<T extends Either<any, any>> = [T] extends [Either<infer _A, infer _E>] ? _A : never
+}
+
 /**
  * Constructs a new `Either` holding a `Right` value. This usually represents a successful value due to the right bias
  * of this structure.

packages/effect/src/Option.ts

@@ -75,6 +75,17 @@ export interface OptionUnify<A extends { [Unify.typeSymbol]?: any }> {
   Option?: () => A[Unify.typeSymbol] extends Option<infer A0> | infer _ ? Option<A0> : never
 }
 
+/**
+ * @since 2.0.0
+ */
+export declare namespace Option {
+  /**
+   * @since 2.0.0
+   * @category type-level
+   */
+  export type Value<T extends Option<any>> = [T] extends [Option<infer _A>] ? _A : never
+}
+
 /**
  * @category models
  * @since 2.0.0