From 37bba43712cd7ccb2d378dec350681fba17d8f7e Mon Sep 17 00:00:00 2001
From: CRIMX <straybugs@gmail.com>
Date: Mon, 18 Dec 2023 19:21:08 +0800
Subject: [PATCH] feat(option): add static isSame

---
 src/option.ts       | 13 +++++++++++++
 test/option.test.ts | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/src/option.ts b/src/option.ts
index 19e1c2a..26055cc 100644
--- a/src/option.ts
+++ b/src/option.ts
@@ -74,6 +74,19 @@ export class Option<T = any> {
   public static isOption<T>(maybeOption: unknown): maybeOption is Option<T> {
     return !!maybeOption && (maybeOption as Option<T>)[OPTION] === 1;
   }
+
+  /**
+   * @returns `true` if the both are `Option` and the value are the same via `Object.is`.
+   *
+   * @param a - An `Option` or any value
+   * @param b - An `Option` or any value
+   */
+  public static isSame(a: unknown, b: unknown): boolean {
+    return Option.isOption(a) && Option.isOption(b)
+      ? Object.is(a._value, b._value)
+      : false;
+  }
+
   private readonly [OPTION] = 1;
 
   private readonly _value: T;
diff --git a/test/option.test.ts b/test/option.test.ts
index 2b6c1d8..744d1f4 100644
--- a/test/option.test.ts
+++ b/test/option.test.ts
@@ -42,6 +42,37 @@ describe("Option", () => {
     });
   });
 
+  describe("isSame", () => {
+    it("returns true if both are the same Some value", () => {
+      const result = Option.isSame(Some("a"), Some("a"));
+      expect(result).toBe(true);
+    });
+
+    it("returns true if both are the same None", () => {
+      const result = Option.isSame(None, None);
+      expect(result).toBe(true);
+    });
+
+    it("returns false when the input is a different Some value", () => {
+      const result = Option.isSame(Some("a"), Some("b"));
+      expect(result).toBe(false);
+    });
+
+    it("returns false when the input is None", () => {
+      const some = Some("hello");
+      const none = None;
+      const result = Option.isSame(some, none);
+      expect(result).toBe(false);
+    });
+
+    it("returns false when the input is a different type", () => {
+      const some = Some("hello");
+      const obj = { value: "hello" };
+      const result = Option.isSame(some, obj);
+      expect(result).toBe(false);
+    });
+  });
+
   describe("isSome", () => {
     it("returns true for a Some", () => {
       const some = Some("hello");
@@ -212,6 +243,13 @@ describe("Option", () => {
       expect(result).toBe(true);
     });
 
+    it("returns true when the input is the same None", () => {
+      const none1 = None;
+      const none2 = None;
+      const result = none1.isSame(none2);
+      expect(result).toBe(true);
+    });
+
     it("returns false when the input is a different Some value", () => {
       const some1 = Some("hello");
       const some2 = Some("world");