diff --git a/benchmark/README.md b/benchmark/README.md
index 006a318..79f6ebf 100644
--- a/benchmark/README.md
+++ b/benchmark/README.md
@@ -4,39 +4,84 @@ Tested on a M1 Pro MacBook Pro.
 
 ## Option
 
+### v8
+
+```
+fp-ts Option none x 134,019,171 ops/sec ±1.58% (94 runs sampled)
+fp-ts Option some x 90,043,117 ops/sec ±3.50% (97 runs sampled)
+fp-ts Option some chain x 2,797,176 ops/sec ±1.35% (97 runs sampled)
+effect Option none x 28,233,747 ops/sec ±0.52% (97 runs sampled)
+effect Option some x 24,837,619 ops/sec ±1.55% (90 runs sampled)
+effect Option some chain x 23,184,057 ops/sec ±3.08% (94 runs sampled)
+Boxed Option none x 610,271,309 ops/sec ±1.22% (98 runs sampled)
+Boxed Option some x 27,055,907 ops/sec ±0.09% (96 runs sampled)
+Boxed Option some flatMap x 26,768,922 ops/sec ±2.66% (88 runs sampled)
+```
+
+### jscore
+
 ```
-fp-ts Option none x 136,289,948 ops/sec ±0.35% (99 runs sampled)
-fp-ts Option some x 92,748,146 ops/sec ±0.36% (95 runs sampled)
-fp-ts Option some chain x 2,831,502 ops/sec ±0.21% (98 runs sampled)
-effect Option none x 28,316,950 ops/sec ±0.68% (90 runs sampled)
-effect Option some x 24,920,467 ops/sec ±0.78% (92 runs sampled)
-effect Option some chain x 24,060,988 ops/sec ±0.31% (99 runs sampled)
-Boxed Option none x 613,986,228 ops/sec ±0.20% (99 runs sampled)
-Boxed Option some x 445,172,964 ops/sec ±0.50% (100 runs sampled)
-Boxed Option some flatMap x 447,362,963 ops/sec ±0.53% (98 runs sampled)
+fp-ts Option none x 26,370,592 ops/sec ±3.01% (80 runs sampled)
+fp-ts Option some x 22,306,443 ops/sec ±3.35% (80 runs sampled)
+fp-ts Option some chain x 6,395,953 ops/sec ±0.72% (94 runs sampled)
+effect Option none x 34,944,770 ops/sec ±3.60% (80 runs sampled)
+effect Option some x 24,062,381 ops/sec ±3.20% (78 runs sampled)
+effect Option some chain x 21,272,877 ops/sec ±3.03% (77 runs sampled)
+Boxed Option none x 360,292,187 ops/sec ±52.07% (26 runs sampled)
+Boxed Option some x 42,614,750 ops/sec ±2.65% (81 runs sampled)
+Boxed Option some flatMap x 39,815,444 ops/sec ±2.15% (85 runs sampled)
 ```
 
 ## Result
 
+### v8
+
+```
+fp-ts Result x 116,486,882 ops/sec ±1.58% (96 runs sampled)
+effect Result x 26,664,690 ops/sec ±1.45% (101 runs sampled)
+Boxed Result x 28,373,628 ops/sec ±2.47% (99 runs sampled)
+```
+
+### jscore
+
 ```
-fp-ts Result x 116,379,320 ops/sec ±0.48% (95 runs sampled)
-effect Result x 26,538,884 ops/sec ±0.43% (96 runs sampled)
-Boxed Result x 422,758,104 ops/sec ±0.98% (94 runs sampled)
+fp-ts Result x 24,241,558 ops/sec ±4.98% (75 runs sampled)
+effect Result x 26,450,388 ops/sec ±2.68% (79 runs sampled)
+Boxed Result x 39,799,836 ops/sec ±2.69% (81 runs sampled)
 ```
 
 ## Future
 
 Careful on the interpretation of the following, as Future doesn't use microtasks and calls its listeners synchronously.
 
+### v8
+
+```
+Promise x 13,345,062 ops/sec ±1.63% (86 runs sampled)
+Future x 163,971 ops/sec ±50.30% (30 runs sampled)
+```
+
+### jscore
+
 ```
-Promise x 13,399,997 ops/sec ±0.57% (81 runs sampled)
-Future x 210,785 ops/sec ±7.41% (32 runs sampled)
+Promise x 6,744,022 ops/sec ±3.20% (83 runs sampled)
+Future x 162,704 ops/sec ±28.63% (24 runs sampled)
 ```
 
 ## Future with Result
 
+### v8
+
+```
+fp-ts TaskEither x 524,318 ops/sec ±1.67% (90 runs sampled)
+effect Effect x 193,219 ops/sec ±0.69% (90 runs sampled)
+Future x 315,497 ops/sec ±10.37% (71 runs sampled)
+```
+
+### jscore
+
 ```
-fp-ts TaskEither x 538,403 ops/sec ±0.29% (86 runs sampled)
-effect Effect x 189,220 ops/sec ±0.94% (87 runs sampled)
-Future x 575,626 ops/sec ±0.30% (90 runs sampled)
+fp-ts TaskEither x 724,358 ops/sec ±7.41% (83 runs sampled)
+effect Effect x 470,137 ops/sec ±0.86% (83 runs sampled)
+Future x 707,572 ops/sec ±2.97% (72 runs sampled)
 ```
diff --git a/src/AsyncData.ts b/src/AsyncData.ts
index 354e4b0..65eb7cc 100644
--- a/src/AsyncData.ts
+++ b/src/AsyncData.ts
@@ -1,9 +1,12 @@
 import { keys, values } from "./Dict";
 import { Option, Result } from "./OptionResult";
+import { createStore } from "./referenceStore";
 import { BOXED_TYPE } from "./symbols";
 import { JsonAsyncData, LooseRecord } from "./types";
 import { zip } from "./ZipUnzip";
 
+const AsyncDataStore = createStore();
+
 class __AsyncData<A> {
   static P = {
     Done: <const A>(value: A) => ({ tag: "Done", value }) as const,
@@ -14,10 +17,16 @@ class __AsyncData<A> {
    * Create an AsyncData.Done value
    */
   static Done = <A = never>(value: A): AsyncData<A> => {
-    const asyncData = Object.create(ASYNC_DATA_PROTO) as Done<A>;
-    asyncData.tag = "Done";
-    asyncData.value = value;
-    return asyncData;
+    const existing = AsyncDataStore.get(value);
+    if (existing === undefined) {
+      const asyncData = Object.create(ASYNC_DATA_PROTO) as Done<A>;
+      asyncData.tag = "Done";
+      asyncData.value = value;
+      AsyncDataStore.set(value, asyncData);
+      return asyncData;
+    } else {
+      return existing as Done<A>;
+    }
   };
 
   /**
diff --git a/src/OptionResult.ts b/src/OptionResult.ts
index 8ed321b..6ad7179 100644
--- a/src/OptionResult.ts
+++ b/src/OptionResult.ts
@@ -1,8 +1,11 @@
 import { keys, values } from "./Dict";
+import { createStore } from "./referenceStore";
 import { BOXED_TYPE } from "./symbols";
 import { JsonOption, JsonResult, LooseRecord } from "./types";
 import { zip } from "./ZipUnzip";
 
+const OptionStore = createStore();
+
 class __Option<A> {
   static P = {
     Some: <const A>(value: A) => ({ tag: "Some", value }) as const,
@@ -10,10 +13,16 @@ class __Option<A> {
   };
 
   static Some = <A = never>(value: A): Option<A> => {
-    const option = Object.create(OPTION_PROTO) as Some<A>;
-    option.tag = "Some";
-    option.value = value;
-    return option;
+    const existing = OptionStore.get(value);
+    if (existing === undefined) {
+      const option = Object.create(OPTION_PROTO) as Some<A>;
+      option.tag = "Some";
+      option.value = value;
+      OptionStore.set(value, option);
+      return option;
+    } else {
+      return existing as Some<A>;
+    }
   };
 
   static None = <A = never>(): Option<A> => NONE as None<A>;
@@ -284,6 +293,9 @@ interface None<A> extends __Option<A> {
 export const Option = __Option;
 export type Option<A> = Some<A> | None<A>;
 
+const OkStore = createStore();
+const ErrorStore = createStore();
+
 class __Result<A, E> {
   static P = {
     Ok: <const A>(value: A) => ({ tag: "Ok", value }) as const,
@@ -291,17 +303,29 @@ class __Result<A, E> {
   };
 
   static Ok = <A = never, E = never>(value: A): Result<A, E> => {
-    const result = Object.create(RESULT_PROTO) as Ok<A, E>;
-    result.tag = "Ok";
-    result.value = value;
-    return result;
+    const existing = OkStore.get(value);
+    if (existing === undefined) {
+      const result = Object.create(RESULT_PROTO) as Ok<A, E>;
+      result.tag = "Ok";
+      result.value = value;
+      OkStore.set(value, result);
+      return result;
+    } else {
+      return existing as Ok<A, E>;
+    }
   };
 
   static Error = <A = never, E = never>(error: E): Result<A, E> => {
-    const result = Object.create(RESULT_PROTO) as Error<A, E>;
-    result.tag = "Error";
-    result.error = error;
-    return result;
+    const existing = ErrorStore.get(error);
+    if (existing === undefined) {
+      const result = Object.create(RESULT_PROTO) as Error<A, E>;
+      result.tag = "Error";
+      result.error = error;
+      ErrorStore.set(error, result);
+      return result;
+    } else {
+      return existing as Error<A, E>;
+    }
   };
 
   static isResult = (value: unknown): value is Result<unknown, unknown> =>
diff --git a/src/referenceStore.ts b/src/referenceStore.ts
new file mode 100644
index 0000000..a6f896f
--- /dev/null
+++ b/src/referenceStore.ts
@@ -0,0 +1,20 @@
+export const createStore = () => {
+  const store = new Map<unknown, WeakRef<object>>();
+
+  const registry = new FinalizationRegistry((value) => {
+    store.delete(value);
+  });
+
+  return {
+    set: (key: unknown, value: object) => {
+      store.set(key, new WeakRef(value));
+      registry.register(value, key);
+    },
+    get: (key: unknown): unknown => {
+      const value = store.get(key);
+      if (value !== undefined) {
+        return value.deref();
+      }
+    },
+  };
+};
diff --git a/test/AsyncData.test.ts b/test/AsyncData.test.ts
index 0426746..25d1261 100644
--- a/test/AsyncData.test.ts
+++ b/test/AsyncData.test.ts
@@ -389,3 +389,10 @@ test("AsyncData JSON serialization", () => {
     }),
   ).toEqual(data);
 });
+
+test("AsyncData equality", () => {
+  expect(AsyncData.Done(1)).toBe(AsyncData.Done(1));
+  expect(AsyncData.Done({})).not.toBe(AsyncData.Done({}));
+  const x = {};
+  expect(AsyncData.Done(x)).toBe(AsyncData.Done(x));
+});
diff --git a/test/Option.test.ts b/test/Option.test.ts
index 14488cf..6b06ba0 100644
--- a/test/Option.test.ts
+++ b/test/Option.test.ts
@@ -211,3 +211,10 @@ test("Option JSON serialization", () => {
     }),
   ).toEqual(option);
 });
+
+test("Option equality", () => {
+  expect(Option.Some(1)).toBe(Option.Some(1));
+  expect(Option.Some({})).not.toBe(Option.Some({}));
+  const x = {};
+  expect(Option.Some(x)).toBe(Option.Some(x));
+});
diff --git a/test/Result.test.ts b/test/Result.test.ts
index 90b4f80..bcf6bd3 100644
--- a/test/Result.test.ts
+++ b/test/Result.test.ts
@@ -269,3 +269,13 @@ test("Result JSON serialization", async () => {
     }),
   ).toEqual(resultError);
 });
+
+test("Result equality", () => {
+  expect(Result.Ok(1)).toBe(Result.Ok(1));
+  expect(Result.Error(1)).toBe(Result.Error(1));
+  expect(Result.Ok({})).not.toBe(Result.Ok({}));
+  expect(Result.Error({})).not.toBe(Result.Error({}));
+  const x = {};
+  expect(Result.Ok(x)).toBe(Result.Ok(x));
+  expect(Result.Error(x)).toBe(Result.Error(x));
+});
diff --git a/tsconfig.json b/tsconfig.json
index ef94261..24c4327 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -3,7 +3,7 @@
   "compilerOptions": {
     "module": "ES2015",
     "target": "ES2015",
-    "lib": ["DOM", "DOM.Iterable", "ES2017"],
+    "lib": ["DOM", "DOM.Iterable", "ES2021"],
     "moduleResolution": "Node",
     "outDir": "dist/",