Merge pull request #260 from kyleve/kve/add-some-changes-to-on-change

Add added and removes to the onContentChanged callback
square · Jan 23, 2021 · ec4c7f9 · ec4c7f9
2 parents 86af8b2 + 6f4d7e1
commit ec4c7f9
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Showing 8 changed files with 241 additions and 109 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -6,6 +6,8 @@
 
 - [Introduce support for layout customization for `Item`, `HeaderFooter`, and `Section`](https://github.com/kyleve/Listable/pull/257) for all `ListLayout` types, not just `.table`.
 
+- [Add `inserted` and `removed` items to `.onContentChanged`](https://github.com/kyleve/Listable/pull/260), to easily determine what content was added or removed from the list a central location.
+
 ### Removed
 
 ### Changed

diff --git a/Demo/Demo.xcodeproj/project.pbxproj b/Demo/Demo.xcodeproj/project.pbxproj
@@ -614,6 +614,7 @@
 				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
 				ENABLE_NS_ASSERTIONS = NO;
 				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				ENABLE_TESTABILITY = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu11;
 				GCC_NO_COMMON_BLOCKS = YES;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;

diff --git a/ListableUI/Sources/Internal/Diff/ArrayDiff.swift b/ListableUI/Sources/Internal/Diff/ArrayDiff.swift
@@ -23,26 +23,34 @@ struct ArrayDiff<Element, Identifier:Hashable>
 
     struct Added
     {
+        let identifier : Identifier
+
         let newIndex : Int
 
         let new : Element
     }
 
     struct Removed
     {
+        let identifier : Identifier
+
         let oldIndex : Int
 
         let old : Element
     }
 
     struct Moved
     {
+        let identifier : Identifier
+
         let old : Removed
         let new : Added
     }
 
     struct Updated
     {
+        let identifier : Identifier
+
         let oldIndex : Int
         let newIndex : Int
 
@@ -52,6 +60,8 @@ struct ArrayDiff<Element, Identifier:Hashable>
 
     struct NoChange
     {
+        let identifier : Identifier
+
         let oldIndex : Int
         let newIndex : Int
 
@@ -105,11 +115,19 @@ struct ArrayDiff<Element, Identifier:Hashable>
         let removed = old.subtractDifference(from: new)
 
         self.added = added.map {
-            Added(newIndex: $0.index, new: $0.value)
+            Added(
+                identifier: $0.identifier.base,
+                newIndex: $0.index,
+                new: $0.value
+            )
         }
 
         self.removed = removed.map {
-            Removed(oldIndex: $0.index, old: $0.value)
+            Removed(
+                identifier: $0.identifier.base,
+                oldIndex: $0.index,
+                old: $0.value
+            )
         }
 
         //
@@ -145,18 +163,30 @@ struct ArrayDiff<Element, Identifier:Hashable>
                 )
 
                 self.moved.append(Moved(
-                    old: Removed(oldIndex: pair.old.index, old: pair.old.value),
-                    new: Added(newIndex: pair.new.index, new: pair.new.value)
+                    identifier: pair.new.identifier.base,
+
+                    old: Removed(
+                        identifier: pair.old.identifier.base,
+                        oldIndex: pair.old.index,
+                        old: pair.old.value
+                    ),
+                    new: Added(
+                        identifier: pair.new.identifier.base,
+                        newIndex: pair.new.index,
+                        new: pair.new.value
+                    )
                 ))
             } else if pair.updated {
                 self.updated.append(Updated(
+                    identifier: pair.new.identifier.base,
                     oldIndex: pair.old.index,
                     newIndex: pair.new.index,
                     old: pair.old.value,
                     new: pair.new.value
                 ))
             } else {
                 self.noChange.append(NoChange(
+                    identifier: pair.new.identifier.base,
                     oldIndex: pair.old.index,
                     newIndex: pair.new.index,
                     old: pair.old.value,
@@ -199,14 +229,32 @@ struct ArrayDiff<Element, Identifier:Hashable>
             let old = old[index]
             let new = new[index]
 
-            guard identifierProvider(old) == identifierProvider(new) else {
+            let newID = identifierProvider(new)
+
+            guard identifierProvider(old) == newID else {
                 return nil
             }
 
             if updated(old, new) {
-                updates.append(Updated(oldIndex: index, newIndex: index, old: old, new: new))
+                updates.append(
+                    Updated(
+                        identifier: newID,
+                        oldIndex: index,
+                        newIndex: index,
+                        old: old,
+                        new: new
+                    )
+                )
             } else {
-                notChanged.append(NoChange(oldIndex: index, newIndex: index, old: old, new: new))
+                notChanged.append(
+                    NoChange(
+                        identifier: newID,
+                        oldIndex: index,
+                        newIndex: index,
+                        old: old,
+                        new: new
+                    )
+                )
             }
         }
 
@@ -423,7 +471,8 @@ private class DiffContainer<Value, Identifier:Hashable>
 
 private struct UniqueIdentifier<Type, Identifier:Hashable> : Hashable
 {
-    private let base : Identifier
+    let base : Identifier
+
     private let modifier : Int
 
     private let hash : Int