Range

orderedmap.go

@@ -76,6 +76,24 @@ func (o *OrderedMap) Delete(key string) {
 	delete(o.values, key)
 }
 
+// Range over the ordered map, accessing entries in the same order they were
+// added, making the traversal deterministic.
+// This API is based on the api `sync.Map.Range`.
+//
+// Provide a call function, `fn`, which will receive the key and value of each
+// iteration. The callback function returns a bool indicating whether or not to
+// continue looping.
+// `true`: continue iteration
+// `false`: break from interation
+func (o *OrderedMap) Range(fn func(key string, value interface{}) bool) {
+	for _, k := range o.keys {
+		v := o.values[k]
+		if !fn(k, v) {
+			break
+		}
+	}
+}
+
 func (o *OrderedMap) Keys() []string {
 	return o.keys
 }

orderedmap_test.go

@@ -69,10 +69,10 @@ func TestOrderedMap(t *testing.T) {
 	// Values method
 	values := o.Values()
 	expectedValues := map[string]interface{}{
-		"number": 4,
-		"string": "x",
+		"number":  4,
+		"string":  "x",
 		"strings": []string{"t", "u"},
-		"mixed": []interface{}{ 1, "1" },
+		"mixed":   []interface{}{1, "1"},
 	}
 	if !reflect.DeepEqual(values, expectedValues) {
 		t.Error("Values method returned unexpected map")
@@ -595,3 +595,68 @@ func TestOrderedMap_empty_map(t *testing.T) {
 		t.Error("Got", marshalledStr)
 	}
 }
+
+func TestOrderedMap_Range(t *testing.T) {
+	tests := map[string]struct {
+		in []struct {
+			k string
+			v int
+		}
+		out       []int
+		rangeFunc func(k string, v interface{}) bool
+	}{
+		"test full range": {
+			in: []struct {
+				k string
+				v int
+			}{
+				{k: "hello", v: 1},
+				{k: "there", v: 2},
+				{k: "outlier", v: 567},
+				{k: "wow", v: 4},
+			},
+			out: []int{1, 2, 567, 4},
+		},
+		"test range with break": {
+			in: []struct {
+				k string
+				v int
+			}{
+				{k: "hello", v: 1},
+				{k: "there", v: 2},
+				{k: "outlier", v: 567},
+				{k: "wow", v: 4},
+			},
+			out: []int{1, 2, 567},
+			rangeFunc: func(k string, v interface{}) bool {
+				return k != "outlier"
+			},
+		},
+	}
+
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			o := New()
+
+			for _, p := range test.in {
+				o.Set(p.k, p.v)
+			}
+
+			var out []int
+			o.Range(func(k string, v interface{}) bool {
+				i, ok := v.(int)
+				if !ok {
+					t.Errorf("%q is not an int. got=%v", k, v)
+				}
+
+				out = append(out, i)
+
+				if test.rangeFunc != nil {
+					return test.rangeFunc(k, v)
+				}
+
+				return true
+			})
+		})
+	}
+}