Add helper protocols for the properties included in the dump

The current method of using the CustomDumpReflectable can work to produce this but it requires a lot more work to implement for each type that needs it.

Sources/CustomDump/CustomDumpChildren.swift

@@ -0,0 +1,97 @@
+/// Implement this protocol to exclude superclass nodes
+public protocol CustomDumpExcludeSuperclass {}
+
+/// Implement this protocol to ignore dumping child nodes
+///
+/// Using this protocol will make the type ignore the children completly and only print out the type name.
+/// This can be useful when something is irrelevant
+public protocol CustomDumpIgnoreChildNodes {}
+
+/// Properties to include child nodes. By default all child nodes are included but when this is implemented, only the values passed will be included in the dump
+///
+/// ```
+/// struct Human {
+/// let name = "Jimmy"
+/// }
+///
+/// struct User: CustomDumpIncludedChildNodesProvider {
+///   static var includedNodes: [String]? {
+///     [
+///       "name",
+///       "email",
+///       "friends",
+///     ]
+///   }
+///   let name = "John"
+///   let email = "[email protected]"
+///   let age = 97
+///   let friends = [
+///     "James",
+///     "Lilly",
+///     "Peter",
+///     "Remus",
+///   ]
+///   let human = Human()
+/// }
+/// ```
+/// The dump for this will produce
+/// ```
+/// User(
+///   name: "John",
+///   email: "[email protected]",
+///   friends: [
+///     [0]: "James",
+///     [1]: "Lilly",
+///     [2]: "Peter",
+///     [3]: "Remus"
+///   ]
+/// )
+/// ```
+public protocol CustomDumpIncludedChildNodesProvider {
+  /// Which nodes to include in the dump
+  static var includedNodes: [String]? { get }
+}
+
+/// Properties to exclude child nodes. This can be helpful when one or more fields are not relevant
+///
+/// ```
+/// struct Human {
+/// let name = "Jimmy"
+/// }
+///
+/// struct User: CustomDumpExcludedChildNodesProvider {
+///   static var excludedNodes: [String] {
+///     [
+///       "age",
+///       "friends"
+///     ]
+///   }
+///   let name = "John"
+///   let email = "[email protected]"
+///   let age = 97
+///   let friends = [
+///     "James",
+///     "Lilly",
+///     "Peter",
+///     "Remus",
+///   ]
+///   let human = Human()
+/// }
+/// ```
+/// The dump for this will produce
+/// ```
+/// User(
+///   name: "John",
+///   email: "[email protected]",
+///   friends: [
+///     [0]: "James",
+///     [1]: "Lilly",
+///     [2]: "Peter",
+///     [3]: "Remus"
+///   ]
+/// )
+/// ```
+public protocol CustomDumpExcludedChildNodesProvider {
+  /// Which nodes to exclude from the dump
+  static var excludedNodes: [String] { get }
+}

Sources/CustomDump/Dump.swift

@@ -82,10 +82,28 @@ public func customDump<T, TargetStream>(
       _ transform: (inout Mirror.Child, Int) -> Void = { _, _ in }
     ) {
       out.write(prefix)
-      if !mirror.children.isEmpty {
+      var children = mirror.children
+      if value is CustomDumpIgnoreChildNodes {
+        out.write("...")
+        out.write(suffix)
+        return
+      }
+      if let value = value as? CustomDumpIncludedChildNodesProvider, let nodes = type(of: value).includedNodes {
+        children = Mirror.Children(children.filter {
+          $0.label.map { nodes.contains($0) } ?? false
+        })
+      }
+      if let value = value as? CustomDumpExcludedChildNodesProvider {
+        let nodes = type(of: value).excludedNodes
+        children = Mirror.Children(children.filter {
+          $0.label.map { !nodes.contains($0) } ?? true
+        })
+      }
+
+      if !children.isEmpty {
         if mirror.isSingleValueContainer {
           var childOut = ""
-          let child = mirror.children.first!
+          let child = children.first!
           customDumpHelp(
             child.value, to: &childOut, name: child.label, indent: 0, maxDepth: maxDepth - 1
           )
@@ -104,7 +122,7 @@ public func customDump<T, TargetStream>(
           out.write("…")
         } else {
           out.write("\n")
-          var children = Array(mirror.children)
+          var children = Array(children)
           if let areInIncreasingOrder = areInIncreasingOrder {
             children.sort(by: areInIncreasingOrder)
           }
@@ -140,10 +158,12 @@ public func customDump<T, TargetStream>(
         visitedItems.insert(item)
         var children = Array(mirror.children)
 
-        var superclassMirror = mirror.superclassMirror
-        while let mirror = superclassMirror {
-          children.insert(contentsOf: mirror.children, at: 0)
-          superclassMirror = mirror.superclassMirror
+        if !(value is CustomDumpExcludeSuperclass) {
+          var superclassMirror = mirror.superclassMirror
+          while let mirror = superclassMirror {
+            children.insert(contentsOf: mirror.children, at: 0)
+            superclassMirror = mirror.superclassMirror
+          }
         }
         dumpChildren(
           of: Mirror(value, children: children),

Tests/CustomDumpTests/DumpTests.swift

@@ -850,6 +850,77 @@ final class DumpTests: XCTestCase {
     )
   }
 
+  func testIncludedNodes() {
+    var dump = ""
+    class Human: CustomDumpIncludedChildNodesProvider {
+      static var includedNodes: [String]? {
+        [
+          "name",
+          "email",
+        ]
+      }
+      let name = "John"
+      let email = "[email protected]"
+      let age = 97
+    }
+
+    customDump(Human(), to: &dump)
+
+    XCTAssertNoDifference(
+      dump,
+      """
+      DumpTests.Human(
+        name: "John",
+        email: "[email protected]"
+      )
+      """
+    )
+  }
+
+  func testExcludedNodes() {
+    var dump = ""
+    class Human: CustomDumpExcludedChildNodesProvider {
+      static var excludedNodes: [String] {
+        [
+          "name",
+        ]
+      }
+      let name = "John"
+      let email = "[email protected]"
+      let age = 97
+    }
+
+    customDump(Human(), to: &dump)
+
+    XCTAssertNoDifference(
+      dump,
+      """
+      DumpTests.Human(
+        email: "[email protected]",
+        age: 97
+      )
+      """
+    )
+  }
+
+  func testIgnoreChildNodes() {
+    var dump = ""
+    class Human: CustomDumpIgnoreChildNodes {
+      let name = "John"
+      let email = "[email protected]"
+      let age = 97
+    }
+
+    customDump(Human(), to: &dump)
+
+    XCTAssertNoDifference(
+      dump,
+      """
+      DumpTests.Human(...)
+      """
+    )
+  }
+
   func testRepeatition() {
     class Human {
       let name = "John"
@@ -871,25 +942,26 @@ final class DumpTests: XCTestCase {
 
     XCTAssertNoDifference(
       dump,
-      """
-      [
-        [0]: DumpTests.Human(
-          name: "John",
-          email: "[email protected]",
-          age: 97
-        ),
-        [1]: DumpTests.Human(↩︎),
-        [2]: DumpTests.Human(
-          name: "John",
-          email: "[email protected]",
-          age: 97
-        ),
-        [3]: DumpTests.Human(↩︎)
-      ]
-      """
+       """
+       [
+         [0]: DumpTests.Human(
+           name: "John",
+           email: "[email protected]",
+           age: 97
+         ),
+         [1]: DumpTests.Human(↩︎),
+         [2]: DumpTests.Human(
+           name: "John",
+           email: "[email protected]",
+           age: 97
+         ),
+         [3]: DumpTests.Human(↩︎)
+       ]
+       """
     )
   }
 
+
   #if canImport(CoreGraphics)
     func testCoreGraphics() {
       var dump = ""