Update

Sources/Verge/Store/StoreDriverType+Accumulator.swift

@@ -1,6 +1,11 @@
 
 extension StoreDriverType {
 
+  /**
+   Subscribes states and accumulates into components.
+   Against sink method, it does not use Changes object.
+   It allows to check if values has changed in the unit of accumulation, not Changes view.
+   */
   public func accumulate<T>(
     queue: MainActorTargetQueue = .mainIsolated(),
     @AccumulationSinkComponentBuilder<Scope> _ buildSubscription: @escaping @MainActor (consuming AccumulationBuilder<Scope>) -> _AccumulationSinkGroup<Scope, T>
@@ -33,6 +38,11 @@ extension StoreDriverType {
 
   }
 
+  /**
+   Subscribes states and accumulates into components.
+   Against sink method, it does not use Changes object.
+   It allows to check if values has changed in the unit of accumulation, not Changes view.
+   */
   @_disfavoredOverload
   public func accumulate<T>(
     queue: some TargetQueueType,

Tests/VergeTests/AccumulationTests.swift

@@ -3,7 +3,7 @@ import XCTest
 
 final class AccumulationTests: XCTestCase {
 
-  func test() {
+  func test_main() {
 
     let store = DemoStore()
 
@@ -13,7 +13,7 @@ final class AccumulationTests: XCTestCase {
     let expForName = expectation(description: "name")
     expForName.expectedFulfillmentCount = 2
 
-    let sub = store.accumulate { [weak self] in
+    let sub = store.accumulate(queue: .mainIsolated()) { [weak self] in
 
       $0.ifChanged(\.count).do { value in
         expForCount.fulfill()
@@ -64,6 +64,61 @@ final class AccumulationTests: XCTestCase {
     let _ = sub
   }
 
+  func test_background() {
+
+    let store = DemoStore()
+
+    let expForCount = expectation(description: "count")
+    expForCount.expectedFulfillmentCount = 2
+
+    let expForName = expectation(description: "name")
+    expForName.expectedFulfillmentCount = 2
+
+    let sub = store.accumulate(queue: .passthrough) { [weak self] in
+
+      $0.ifChanged(\.count).do { value in
+        expForCount.fulfill()
+      }
+
+      $0.ifChanged(\.name).do { value in
+        expForName.fulfill()
+      }
+
+      // checks for result builders
+      if let _ = self {
+        $0.ifChanged(\.name).do { value in
+        }
+      }
+
+      // checks for result builders
+      if true {
+        $0.ifChanged(\.name).do { value in
+        }
+      } else {
+        $0.ifChanged(\.name).do { value in
+        }
+      }
+
+      // checks for result builders
+      if true {
+        $0.ifChanged(\.name).do { value in
+        }
+      }
+
+    }
+
+    store.commit {
+      $0.count += 1
+    }
+
+    store.commit {
+      $0.name = "name"
+    }
+
+    wait(for: [expForCount, expForName], timeout: 1)
+
+    let _ = sub
+  }
 }
 
 @MainActor