From 6223343039dd226991f570a3ad3fa165ce8354b5 Mon Sep 17 00:00:00 2001
From: d5ng <dong5ffice@gmail.com>
Date: Sat, 22 Mar 2025 00:00:02 +0900
Subject: [PATCH 1/3] =?UTF-8?q?=E2=9C=A8=20Feat:=20bind=20=ED=95=A8?=
 =?UTF-8?q?=EC=88=98=20=EA=B5=AC=ED=98=84?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 assignment/src/bind.test.ts | 28 ++++++++++++++++++++++++++++
 assignment/src/bind.ts      | 21 +++++++++++++++++++++
 2 files changed, 49 insertions(+)
 create mode 100644 assignment/src/bind.test.ts
 create mode 100644 assignment/src/bind.ts

diff --git a/assignment/src/bind.test.ts b/assignment/src/bind.test.ts
new file mode 100644
index 0000000..3a79eb4
--- /dev/null
+++ b/assignment/src/bind.test.ts
@@ -0,0 +1,28 @@
+import { bind } from "./bind"
+
+describe("bind 함수 테스트", () => {
+  test("bind Partial", () => {
+    function greet(this: { name: string }, greeting: string, punctuation: string) {
+      return `${greeting}, ${this.name}${punctuation}`
+    }
+
+    const person = { name: "Alice" }
+    const greetAlice = bind(greet, person, "Hello")
+
+    expect(greetAlice("!")).toBe("Hello, Alice!")
+  })
+
+  test("생성자 함수 테스트", () => {
+    // 즉 생성자 함수를 사용할 때에도 this binding이 되야함
+    // 어떻게?
+    function Person(this: Record<string, any>, name: string) {
+      this.name = name
+    }
+
+    const BoundPerson = bind(Person, { name: "notUsed" })
+    const p = new BoundPerson("Tom")
+
+    expect(p.name).toBe("Tom")
+    expect(p instanceof Person).true
+  })
+})
diff --git a/assignment/src/bind.ts b/assignment/src/bind.ts
new file mode 100644
index 0000000..571361f
--- /dev/null
+++ b/assignment/src/bind.ts
@@ -0,0 +1,21 @@
+type BindThis<T, U> = T extends (this: any, ...args: infer A) => infer R ? (this: U, ...args: A) => R : never
+
+type PartiallyBound<T, P extends any[]> = T extends (...args: [...P, ...infer Rest]) => infer R
+  ? (...args: Rest) => R
+  : never
+
+export function bind<T extends (this: any, ...args: any[]) => any, U, P extends any[]>(fn: T, thisArg: U, ...args: P) {
+  function boundFn(...args2: any[]) {
+    const isInstnace = this instanceof boundFn
+
+    if (isInstnace) {
+      return fn.call(this, ...args, ...args2)
+    }
+
+    return fn.call(thisArg, ...args, ...args2) as PartiallyBound<BindThis<T, U>, P>
+  }
+
+  boundFn.prototype = Object.create(fn.prototype)
+
+  return boundFn
+}

From c015341903098959cf79ec16b76b9253566078e2 Mon Sep 17 00:00:00 2001
From: d5ng <dong5ffice@gmail.com>
Date: Sat, 22 Mar 2025 00:04:51 +0900
Subject: [PATCH 2/3] =?UTF-8?q?=E2=9C=85=20Test:=20=ED=85=8C=EC=8A=A4?=
 =?UTF-8?q?=ED=8A=B8=20=EC=BD=94=EB=93=9C=20=EC=B6=94=EB=9D=BC=20(Binding)?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 assignment/src/bind.test.ts | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/assignment/src/bind.test.ts b/assignment/src/bind.test.ts
index 3a79eb4..9e61f3b 100644
--- a/assignment/src/bind.test.ts
+++ b/assignment/src/bind.test.ts
@@ -1,6 +1,17 @@
 import { bind } from "./bind"
 
 describe("bind 함수 테스트", () => {
+  test("bind Basic", () => {
+    const users = { name: "d5ng" }
+
+    function getName(this: { name: string }) {
+      return `내 이름은 ${this.name}이에요!`
+    }
+
+    const bindingUser = bind(getName, users)
+    expect(bindingUser()).toBe("내 이름은 d5ng이에요!")
+  })
+
   test("bind Partial", () => {
     function greet(this: { name: string }, greeting: string, punctuation: string) {
       return `${greeting}, ${this.name}${punctuation}`
@@ -13,8 +24,6 @@ describe("bind 함수 테스트", () => {
   })
 
   test("생성자 함수 테스트", () => {
-    // 즉 생성자 함수를 사용할 때에도 this binding이 되야함
-    // 어떻게?
     function Person(this: Record<string, any>, name: string) {
       this.name = name
     }

From 94a9a9b53f8ec9ba48875c7e6127254280aa86c1 Mon Sep 17 00:00:00 2001
From: d5ng <dong5ffice@gmail.com>
Date: Sun, 23 Mar 2025 18:31:57 +0900
Subject: [PATCH 3/3] =?UTF-8?q?=E2=99=BB=EF=B8=8F=20Refactor:=20boundFn=20?=
 =?UTF-8?q?=ED=83=80=EC=9E=85=20=EC=88=98=EC=A0=95?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 assignment/src/bind.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/assignment/src/bind.ts b/assignment/src/bind.ts
index 571361f..9773ac0 100644
--- a/assignment/src/bind.ts
+++ b/assignment/src/bind.ts
@@ -5,7 +5,7 @@ type PartiallyBound<T, P extends any[]> = T extends (...args: [...P, ...infer Re
   : never
 
 export function bind<T extends (this: any, ...args: any[]) => any, U, P extends any[]>(fn: T, thisArg: U, ...args: P) {
-  function boundFn(...args2: any[]) {
+  function boundFn(this: any, ...args2: any[]) {
     const isInstnace = this instanceof boundFn
 
     if (isInstnace) {