From c261e661261e6c49428af5627224b4c744c9860a Mon Sep 17 00:00:00 2001
From: "maksim.khramtsov" <maksim.khramtsov@btsdigital.kz>
Date: Mon, 24 Jun 2024 11:18:18 +0200
Subject: [PATCH] Support `this` argument for `Micro.gen`

---
 .changeset/early-olives-lay.md     |  5 +++++
 packages/effect/src/Micro.ts       | 12 ++++++++++--
 packages/effect/test/Micro.test.ts | 21 +++++++++++++++------
 3 files changed, 30 insertions(+), 8 deletions(-)
 create mode 100644 .changeset/early-olives-lay.md

diff --git a/.changeset/early-olives-lay.md b/.changeset/early-olives-lay.md
new file mode 100644
index 0000000000..dc14b090d7
--- /dev/null
+++ b/.changeset/early-olives-lay.md
@@ -0,0 +1,5 @@
+---
+"effect": minor
+---
+
+Support `this` argument for `Micro.gen`
diff --git a/packages/effect/src/Micro.ts b/packages/effect/src/Micro.ts
index 7d5be32bb0..2bd7a94b83 100644
--- a/packages/effect/src/Micro.ts
+++ b/packages/effect/src/Micro.ts
@@ -1223,14 +1223,22 @@ export const never: Micro<never> = async<never>(function() {
  * @experimental
  * @category constructors
  */
-export const gen = <Eff extends YieldWrap<Micro<any, any, any>>, AEff>(
-  f: () => Generator<Eff, AEff, never>
+export const gen = <Self, Eff extends YieldWrap<Micro<any, any, any>>, AEff>(
+  ...args:
+    | [self: Self, body: (this: Self) => Generator<Eff, AEff, never>]
+    | [body: () => Generator<Eff, AEff, never>]
 ): Micro<
   AEff,
   [Eff] extends [never] ? never : [Eff] extends [YieldWrap<Micro<infer _A, infer E, infer _R>>] ? E : never,
   [Eff] extends [never] ? never : [Eff] extends [YieldWrap<Micro<infer _A, infer _E, infer R>>] ? R : never
 > =>
   make(function(env, onResult) {
+    let f: () => Generator<Eff, AEff, never>
+    if (args.length === 1) {
+      f = args[0]
+    } else {
+      f = args[1].bind(args[0])
+    }
     const iterator = f() as Iterator<YieldWrap<Micro<any, any, any>>, AEff, any>
     let running = false
     let value: any = undefined
diff --git a/packages/effect/test/Micro.test.ts b/packages/effect/test/Micro.test.ts
index aaf9e17c90..f9a37e99fa 100644
--- a/packages/effect/test/Micro.test.ts
+++ b/packages/effect/test/Micro.test.ts
@@ -106,12 +106,21 @@ describe.concurrent("Micro", () => {
       Micro.runPromise
     ))
 
-  it("gen", () =>
-    Micro.gen(function*() {
-      const result = yield* Micro.succeed(1)
-      assert.strictEqual(result, 1)
-      return result
-    }).pipe(Micro.runPromise).then((_) => assert.deepStrictEqual(_, 1)))
+  describe("gen", () => {
+    it("gen", () =>
+      Micro.gen(function*() {
+        const result = yield* Micro.succeed(1)
+        assert.strictEqual(result, 1)
+        return result
+      }).pipe(Micro.runPromise).then((_) => assert.deepStrictEqual(_, 1)))
+
+    it("gen with context", () =>
+      Micro.gen({ a: 1, b: 2 }, function*() {
+        const result = yield* Micro.succeed(this.a)
+        assert.strictEqual(result, 1)
+        return result + this.b
+      }).pipe(Micro.runPromise).then((_) => assert.deepStrictEqual(_, 3)))
+  })
 
   describe("forEach", () => {
     it("sequential", () =>