Merge pull request #253 from hotwired/bridge-delegate-destination-lifecycle

Keep bridge destinations active while attached

Author: svara

Source/Bridge/BridgeDelegate.swift

@@ -52,7 +52,6 @@ public final class BridgeDelegate: BridgingDelegate {
     public func webViewDidBecomeActive(_ webView: WKWebView) {
         bridge = Bridge.getBridgeFor(webView)
         bridge?.delegate = self
-        destinationIsActive = true
 
         if bridge == nil {
             logger.warning("bridgeNotInitializedForWebView")
@@ -62,7 +61,6 @@ public final class BridgeDelegate: BridgingDelegate {
     public func webViewDidBecomeDeactivated() {
         bridge?.delegate = nil
         bridge = nil
-        destinationIsActive = false
     }
 
     @discardableResult
@@ -84,19 +82,16 @@ public final class BridgeDelegate: BridgingDelegate {
 
     public func onViewDidLoad() {
         logger.debug("[Bridge] bridgeDestinationViewDidLoad: \(self.resolvedLocation)")
-        destinationIsActive = true
         activeComponents.forEach { $0.viewDidLoad() }
     }
 
     public func onViewWillAppear() {
         logger.debug("[Bridge] bridgeDestinationViewWillAppear: \(self.resolvedLocation)")
-        destinationIsActive = true
         activeComponents.forEach { $0.viewWillAppear() }
     }
 
     public func onViewDidAppear() {
         logger.debug("[Bridge] bridgeDestinationViewDidAppear: \(self.resolvedLocation)")
-        destinationIsActive = true
         activeComponents.forEach { $0.viewDidAppear() }
     }
 
@@ -107,7 +102,6 @@ public final class BridgeDelegate: BridgingDelegate {
 
     public func onViewDidDisappear() {
         activeComponents.forEach { $0.viewDidDisappear() }
-        destinationIsActive = false
         logger.debug("[Bridge] bridgeDestinationViewDidDisappear: \(self.resolvedLocation)")
     }
 
@@ -147,14 +141,20 @@ public final class BridgeDelegate: BridgingDelegate {
     // MARK: Private
 
     private var initializedComponents: [String: BridgeComponent] = [:]
-    private var destinationIsActive = false
     private let componentTypes: [BridgeComponent.Type]
+    private var destinationIsActive: Bool {
+        bridge != nil
+    }
     private var resolvedLocation: String {
         webView?.url?.absoluteString ?? location
     }
 
     private var activeComponents: [BridgeComponent] {
-        return initializedComponents.values.filter { _ in destinationIsActive }
+        guard destinationIsActive else {
+            return []
+        }
+
+        return Array(initializedComponents.values)
     }
 
     private func getOrCreateComponent(name: String) -> BridgeComponent? {

Tests/Bridge/BridgeDelegate+DestinationTests.swift

@@ -57,17 +57,21 @@ class BridgeDelegateDestinationTests: XCTestCase {
         XCTAssertNotNil(component)
     }
 
-    func testBridgeDestinationIsInactiveAfterViewDidDisappear() {
+    func testBridgeDestinationRemainsActiveAfterViewDidDisappearWhenWebViewIsStillActive() {
+        // Tab bar destinations can receive view disappearance callbacks while
+        // their web view remains active and attached to the bridge.
         delegate.onViewDidLoad()
         delegate.onViewDidDisappear()
         delegate.bridgeDidReceiveMessage(.test)
 
         let component: BridgeComponentSpy? = delegate.component()
-        XCTAssertNil(component)
+        XCTAssertNotNil(component)
     }
 
     func testBridgeDestinationIsActiveAfterWebViewDidBecomeActive() {
-        delegate.webViewDidBecomeActive(WKWebView())
+        let webView = WKWebView()
+        Bridge.initialize(webView)
+        delegate.webViewDidBecomeActive(webView)
         delegate.bridgeDidReceiveMessage(.test)
 
         let component: BridgeComponentSpy? = delegate.component()

Tests/Bridge/BridgeDelegateTests.swift

@@ -125,7 +125,7 @@ class BridgeDelegateTests: XCTestCase {
         XCTAssertNotNil(component?.delegate)
     }
 
-    func testBridgeIgnoresMessageForInactiveDestination() {
+    func testBridgeIgnoresMessageAfterWebViewBecomesDeactivated() {
         let message = Message(id: "1",
                               component: "one",
                               event: "connect",
@@ -137,7 +137,7 @@ class BridgeDelegateTests: XCTestCase {
         var component: OneBridgeComponent? = delegate.component()
         XCTAssertNotNil(component)
 
-        delegate.onViewDidDisappear()
+        delegate.webViewDidBecomeDeactivated()
         XCTAssertFalse(delegate.bridgeDidReceiveMessage(message))
 
         component = delegate.component()