⭐️ Impl: Add Collection+Helpers

ios/src_library/Extensions/Collection+Helpers.swift

@@ -0,0 +1,41 @@
+//
+//  Collection+Helpers.swift
+//  react-native-ios-modal
+//
+//  Created by Dominic Go on 4/10/23.
+//
+
+import Foundation
+
+extension Collection {
+
+  public var secondToLast: Element? {
+    self[safeIndex: self.index(self.indices.endIndex, offsetBy: -2)];
+  };
+
+  public func isOutOfBounds(forIndex index: Index) -> Bool {
+    return index < self.indices.startIndex || index > self.indices.endIndex;
+  };
+
+  /// Returns the element at the specified index if it is within bounds,
+  /// otherwise nil.
+  public subscript(safeIndex index: Index) -> Element? {
+    return self.isOutOfBounds(forIndex: index) ? nil : self[index];
+  };
+};
+
+extension MutableCollection {
+  subscript(safeIndex index: Index) -> Element? {
+    get {
+      return self.isOutOfBounds(forIndex: index) ? nil : self[index];
+    }
+
+    set {
+      guard let newValue = newValue,
+            !self.isOutOfBounds(forIndex: index)
+      else { return };
+
+      self[index] = newValue;
+    }
+  };
+};