simplify async constructors (#1715)

.changeset/cool-foxes-press.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+only add onInterrupt in Effect.async if required

.changeset/quiet-turkeys-bake.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+simplify Effect.tryCatch implementation

src/internal/core-effect.ts

@@ -1629,7 +1629,6 @@ export const tryPromise: {
 ): Effect.Effect<never, E | Cause.UnknownException, A> => {
   let evaluate: (signal?: AbortSignal) => Promise<A>
   let catcher: ((error: unknown) => E) | undefined = undefined
-
   if (typeof arg === "function") {
     evaluate = arg as (signal?: AbortSignal) => Promise<A>
   } else {
@@ -1638,40 +1637,38 @@ export const tryPromise: {
   }
 
   if (evaluate.length >= 1) {
-    return core.suspend(() => {
-      const controller = new AbortController()
-      return core.flatMap(try_(() => evaluate(controller.signal)), (promise) =>
-        core.async((resolve) => {
-          promise
-            .then((a) => resolve(core.exitSucceed(a)))
-            .catch((e) =>
-              resolve(core.fail(
-                catcher ? catcher(e) : new core.UnknownException(e)
-              ))
-            )
-          return core.sync(() => controller.abort())
-        }))
-    })
-  }
-
-  return core.flatMap(
-    try_(
-      arg as {
-        readonly try: LazyArg<Promise<A>>
-        readonly catch: (error: unknown) => E
-      }
-    ),
-    (promise) =>
-      core.async((resolve) => {
-        promise
+    return core.async((resolve, signal) => {
+      try {
+        evaluate(signal)
           .then((a) => resolve(core.exitSucceed(a)))
           .catch((e) =>
             resolve(core.fail(
               catcher ? catcher(e) : new core.UnknownException(e)
             ))
           )
-      })
-  )
+      } catch (e) {
+        resolve(core.fail(
+          catcher ? catcher(e) : new core.UnknownException(e)
+        ))
+      }
+    })
+  }
+
+  return core.async((resolve) => {
+    try {
+      evaluate()
+        .then((a) => resolve(core.exitSucceed(a)))
+        .catch((e) =>
+          resolve(core.fail(
+            catcher ? catcher(e) : new core.UnknownException(e)
+          ))
+        )
+    } catch (e) {
+      resolve(core.fail(
+        catcher ? catcher(e) : new core.UnknownException(e)
+      ))
+    }
+  })
 }
 
 /* @internal */

src/internal/core.ts

@@ -439,28 +439,41 @@ export const async = <R, E, A>(
   blockingOn: FiberId.FiberId = FiberId.none
 ): Effect.Effect<R, E, A> =>
   suspend(() => {
+    let backingResume: ((_: Effect.Effect<R, E, A>) => void) | undefined = undefined
+    let pendingEffect: Effect.Effect<R, E, A> | undefined = undefined
+    function proxyResume(effect: Effect.Effect<R, E, A>) {
+      if (backingResume) {
+        backingResume(effect)
+      } else if (pendingEffect === undefined) {
+        pendingEffect = effect
+      }
+    }
+    const effect = new EffectPrimitive(OpCodes.OP_ASYNC) as any
+    effect.i0 = (resume: (_: Effect.Effect<R, E, A>) => void) => {
+      backingResume = resume
+      if (pendingEffect) {
+        resume(pendingEffect)
+      }
+    }
+    effect.i1 = blockingOn
+
     let cancelerRef: Effect.Effect<R, never, void> | void = undefined
     let controllerRef: AbortController | void = undefined
-    const effect = new EffectPrimitive(OpCodes.OP_ASYNC) as any
     if (register.length !== 1) {
-      const controller = new AbortController()
-      controllerRef = controller
-      effect.i0 = (resume: (_: Effect.Effect<R, E, A>) => void) => {
-        cancelerRef = register(resume, controller.signal)
-      }
+      controllerRef = new AbortController()
+      cancelerRef = register(proxyResume, controllerRef.signal)
     } else {
-      effect.i0 = (resume: (_: Effect.Effect<R, E, A>) => void) => {
-        // @ts-expect-error
-        cancelerRef = register(resume)
-      }
+      cancelerRef = (register as any)(proxyResume)
     }
-    effect.i1 = blockingOn
-    return onInterrupt(effect, () => {
-      if (controllerRef) {
-        controllerRef.abort()
-      }
-      return cancelerRef ?? unit
-    })
+
+    return (cancelerRef || controllerRef) ?
+      onInterrupt(effect, (_) => {
+        if (controllerRef) {
+          controllerRef.abort()
+        }
+        return cancelerRef ?? unit
+      }) :
+      effect
   })
 
 /* @internal */