Add FilterOut method (#80)

Co-authored-by: Fenjin Wang <wangfenjin@bytedance.com>

Author: wangfenjin

diff.go

@@ -108,6 +108,19 @@ func StructValues(t string, path []string, s interface{}) (Changelog, error) {
 	return d.cl, d.structValues(t, path, v)
 }
 
+// FilterOut filter out the changes based on path. Paths may contain valid regexp to match items
+func (cl *Changelog) FilterOut(path []string) Changelog {
+	var ncl Changelog
+
+	for _, c := range *cl {
+		if !pathmatch(path, c.Path) {
+			ncl = append(ncl, c)
+		}
+	}
+
+	return ncl
+}
+
 // Filter filter changes based on path. Paths may contain valid regexp to match items
 func (cl *Changelog) Filter(path []string) Changelog {
 	var ncl Changelog

diff_test.go

@@ -758,6 +758,32 @@ func TestFilter(t *testing.T) {
 	}
 }
 
+func TestFilterOut(t *testing.T) {
+	cases := []struct {
+		Name     string
+		Filter   []string
+		Expected [][]string
+	}{
+		{"simple", []string{"item-1", "subitem"}, [][]string{{"item-2", "subitem"}}},
+		{"regex", []string{"item-*"}, [][]string{}},
+	}
+
+	cl := diff.Changelog{
+		{Path: []string{"item-1", "subitem"}},
+		{Path: []string{"item-2", "subitem"}},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.Name, func(t *testing.T) {
+			ncl := cl.FilterOut(tc.Filter)
+			assert.Len(t, ncl, len(tc.Expected))
+			for i, e := range tc.Expected {
+				assert.Equal(t, e, ncl[i].Path)
+			}
+		})
+	}
+}
+
 func TestStructValues(t *testing.T) {
 	cases := []struct {
 		Name       string