added extensions for array

Author: Philipp Homann

Sources/CoreUsefulSDK/Extensions/Array+Unique.swift

@@ -0,0 +1,59 @@
+//
+//  Array+Utils.swift
+//  DigitalAssortmentPlanner
+//
+//  Created by Philipp Homann on 26.05.20.
+//  Copyright © 2020 Endava All rights reserved.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+
+import Foundation
+
+
+
+public extension Array where Element : Hashable {
+    
+    /// returns an unique array without dublicated items
+    var unique: [Element] {
+        return Array(Set(self))
+    }
+}
+
+
+/// appends an item only if it is not contained
+public extension RangeReplaceableCollection where Element: Equatable {
+    @discardableResult
+    mutating func appendIfNotContains(_ element: Element) -> (appended: Bool, memberAfterAppend: Element) {
+        if let index = firstIndex(of: element) {
+            return (false, self[index])
+        } else {
+            append(element)
+            return (true, element)
+        }
+    }
+}
+
+
+public extension Collection {
+    subscript(safe index: Index) -> Iterator.Element? {
+        guard indices.contains(index) else { return nil }
+        return self[index]
+    }
+}