uniq

docs/templatefuncs.md

@@ -262,3 +262,13 @@ FOOBAR
 
 foobar
 ```
+
+## `uniq` *list*
+
+`uniq` returns a new list containing only unique elements in *list*.
+
+```text
+{{ list 1 2 1 3 3 2 1 2 | uniq }}
+
+[1 2 3]
+```

templatefuncs.go

@@ -58,6 +58,7 @@ func NewFuncMap() template.FuncMap {
 		"toString":         toStringTemplateFunc,
 		"toUpper":          eachString(strings.ToUpper),
 		"trimSpace":        eachString(strings.TrimSpace),
+		"uniq":             uniqTemplateFunc,
 	}
 }
 
@@ -277,7 +278,22 @@ func toStringTemplateFunc(arg any) string {
 	}
 }
 
-// convertAndSortSlice converts a `[]any` to a `[]T` and sorts it.
+// uniqTemplateFunc is the core implementation of the `uniq` template function.
+func uniqTemplateFunc(list []any) []any {
+	seen := make(map[any]struct{})
+	result := []any{}
+
+	for _, v := range list {
+		if _, ok := seen[v]; !ok {
+			result = append(result, v)
+			seen[v] = struct{}{}
+		}
+	}
+
+	return result
+}
+
+// convertAndSortSlice creates a `[]T` copy of its input and sorts it.
 func convertAndSortSlice[T cmp.Ordered](slice []any) []T {
 	l := make([]T, len(slice))
 	for i, elem := range slice {

templatefuncs_test.go

@@ -169,6 +169,10 @@ func TestFuncMap(t *testing.T) {
 			template: `{{ trimSpace " a " }}`,
 			expected: "a",
 		},
+		{
+			template: `{{ list 1 2 1 3 3 2 1 2 | uniq }}`,
+			expected: "[1 2 3]",
+		},
 	} {
 		t.Run(strconv.Itoa(i), func(t *testing.T) {
 			tmpl, err := template.New("").Funcs(funcMap).Parse(tc.template)