snapshot of https://github.com/mattermost/mattermost.git (master, 2026-09-16; blobs > 131072B omitted)

server/public/utils/array.go

@@ -0,0 +1,68 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package utils
+
+// Dedup returns a new slice with duplicate elements removed, preserving the order in which
+// each element first appears. A nil input returns nil, so callers that distinguish "absent"
+// from "empty" keep that distinction.
+func Dedup[T comparable](arr []T) []T {
+	if arr == nil {
+		return nil
+	}
+
+	seen := make(map[T]struct{}, len(arr))
+	result := make([]T, 0, len(arr))
+
+	for _, elem := range arr {
+		if _, ok := seen[elem]; ok {
+			continue
+		}
+
+		seen[elem] = struct{}{}
+		result = append(result, elem)
+	}
+
+	return result
+}
+
+// FindExclusives returns three arrays:
+// 1. Items exclusive to arr1
+// 2. Items exclusive to arr2
+// 3. Items common to both arr1 and arr2
+func FindExclusives[T comparable](arr1, arr2 []T) ([]T, []T, []T) {
+	// Create maps to track the presence of elements in each array
+	existsInArr1 := make(map[T]bool)
+	existsInArr2 := make(map[T]bool)
+
+	// Populate the maps with the elements from both arrays
+	for _, elem := range arr1 {
+		existsInArr1[elem] = true
+	}
+	for _, elem := range arr2 {
+		existsInArr2[elem] = true
+	}
+
+	// Slices for results
+	var uniqueToArr1 []T
+	var uniqueToArr2 []T
+	var common []T
+
+	// Find elements unique to arr1 and common elements
+	for elem := range existsInArr1 {
+		if existsInArr2[elem] {
+			common = append(common, elem)
+		} else {
+			uniqueToArr1 = append(uniqueToArr1, elem)
+		}
+	}
+
+	// Find elements unique to arr2
+	for elem := range existsInArr2 {
+		if !existsInArr1[elem] {
+			uniqueToArr2 = append(uniqueToArr2, elem)
+		}
+	}
+
+	return uniqueToArr1, uniqueToArr2, common
+}