simplify Do by removing unwrapping function

.changeset/nine-terms-agree.md

@@ -0,0 +1,27 @@
+---
+"ftld": major
+---
+
+Simplify Do, remove promise support.
+
+Do no longer needs the unwrapper function.
+
+```
+// before
+const x = Do(function*($) {
+  const a = yield* $(Result.Ok(1))
+  const b = yield* $(Option.Some(2))
+  return a + b;
+});
+
+// after
+const x = Do(function*() {
+  const a = yield* Result.Ok(1);
+  const b = yield* Option.Some(2);
+  return a + b;
+});
+```
+
+A side effect of this is that unwrapping promises is no longer supported. This is a breaking change, but it is for the better.
+
+Promises are not a good fit for the Do notation, and it is better to use async/await instead. Promises also have no way of tracking the Error type, which is a big limitation.

README.md

@@ -794,23 +794,19 @@ function doSomething(): AsyncTask<
   SomeError | OtherError | UnwrapNoneError, // <-- notice how the Option type has an error type
   number
 > {
-  return Do(function* ($) {
-    const a: number = yield* $(
-      Result.from(
-        () => 1,
-        () => new SomeError()
-      )
+  return Do(function* () {
+    const a: number = yield* Result.from(
+      () => 1,
+      () => new SomeError()
     );
 
     // async!
-    const b: number = yield* $(
-      Task.from(
-        async () => 2,
-        () => new OtherError()
-      )
+    const b: number = yield* Task.from(
+      async () => 2,
+      () => new OtherError()
     );
 
-    const c: number = yield* $(Option.from(3 as number | null));
+    const c: number = yield* Option.from(3 as number | null);
 
     return a + b + c;
   });
@@ -822,50 +818,21 @@ function doSomething(): SyncTask<
   number
 > {
   return Do(function* ($) {
-    const a: number = yield* $(
-      Result.from(
-        () => 1,
-        () => new SomeError()
-      )
+    const a: number = yield* Result.from(
+      () => 1,
+      () => new SomeError()
     );
 
-    const b: number = yield* $(
-      Result.from(
-        () => 2,
-        () => new OtherError()
-      )
+    const b: number = yield* Result.from(
+      () => 2,
+      () => new OtherError()
     );
 
-    const c: number = yield* $(Option.from(3 as number | null));
+    const c: number = yield* Option.from(3 as number | null);
 
     return a + b + c;
   });
 }
-
-// you can also use Do with Promises
-// and quickly declare the error type
-
-async function calculateNum(): Promise<number>;
-
-function doSomething(): AsyncTask<SomeError | AnotherError, number> {
-  return Do(function* ($) {
-    const a = yield* $(
-      calculateNum(),
-      (e) => new SomeError() // <-- notice how the error can be mapped over
-      //^-- the error type is inferred initially as unknown which captures the initial error in a value `.error`
-    );
-
-    // can quickly override the error type for any type
-    const b = yield* $(
-      Task.from(
-        () => 1,
-        () => new OtherError()
-      ),
-      (e: OtherError) => new AnotherError()
-      // ^-- the error type is inferred
-    );
-  });
-}
 ```
 
 ## Recipes

lib/package.json

@@ -41,12 +41,12 @@
     "test:coverage": "vitest run --coverage && open coverage/index.html"
   },
   "devDependencies": {
-    "@vitest/coverage-v8": "^1.5.0",
-    "bunchee": "^5.1.2",
+    "@vitest/coverage-v8": "^1.5.2",
+    "bunchee": "^5.1.3",
     "concurrently": "^8.2.2",
     "typescript": "^5.4.5",
-    "undici": "^6.13.0",
-    "vitest": "^1.5.0"
+    "undici": "^6.14.1",
+    "vitest": "^1.5.2"
   },
   "files": [
     "dist"