Add support for localized layouts and regions, data for 14 countries.

Expanded address formats for AE, AM, CA, CN, EG, HK, JP, KP, KR, TH, TW, RU, UA, VN.

address.go

@@ -33,7 +33,9 @@ func (a Address) IsEmpty() bool {
 
 // Format represents an address format.
 type Format struct {
+	Locale            Locale
 	Layout            string
+	LocalLayout       string
 	Required          []Field
 	SublocalityType   SublocalityType
 	LocalityType      LocalityType
@@ -42,6 +44,7 @@ type Format struct {
 	PostalCodePattern string
 	ShowRegionID      bool
 	Regions           map[string]string
+	LocalRegions      map[string]string
 }
 
 // IsRequired returns whether the given field is required.
@@ -84,6 +87,33 @@ func (f Format) CheckPostalCode(postalCode string) bool {
 	return rx.MatchString(postalCode)
 }
 
+// SelectLayout selects the correct layout for the given locale.
+func (f Format) SelectLayout(locale Locale) string {
+	if f.LocalLayout != "" && f.useLocalData(locale) {
+		return f.LocalLayout
+	}
+	return f.Layout
+}
+
+// SelectRegions selects the correct regions for the given locale.
+func (f Format) SelectRegions(locale Locale) map[string]string {
+	if len(f.LocalRegions) > 0 && f.useLocalData(locale) {
+		return f.LocalRegions
+	}
+	return f.Regions
+}
+
+// useLocalData returns whether local data should be used for the given locale.
+func (f Format) useLocalData(locale Locale) bool {
+	if locale.Script == "Latn" {
+		// Allow locales to opt out of local data. E.g: zh-Latn.
+		return false
+	}
+	// Scripts are not compared, matching libaddressinput behavior. This means
+	// that zh-Hant data will be shown to zh-Hans users, and vice-versa.
+	return locale.Language == f.Locale.Language
+}
+
 // CheckCountryCode checks whether the given country code is valid.
 //
 // An empty country code is considered valid.

address_test.go

@@ -121,6 +121,83 @@ func TestFormat_CheckPostalCode(t *testing.T) {
 	}
 }
 
+func TestFormat_SelectLayout(t *testing.T) {
+	tests := []struct {
+		countryCode string
+		locale      string
+		wantLocal   bool
+	}{
+		// China ("zh").
+		{"CN", "en", false},
+		{"CN", "ja", false},
+		{"CN", "zh-Latn", false},
+		{"CN", "zh", true},
+		{"CN", "zh-Hant", true},
+		// Hong Kong ("zh-Hant").
+		{"HK", "en", false},
+		{"HK", "ja", false},
+		{"HK", "zh-Latn", false},
+		{"HK", "zh", true},
+		{"HK", "zh-Hant", true},
+		// Serbia (no local layout defined).
+		{"RS", "en", false},
+	}
+
+	for _, tt := range tests {
+		t.Run("", func(t *testing.T) {
+			locale := address.NewLocale(tt.locale)
+			format := address.GetFormat(tt.countryCode)
+			got := format.SelectLayout(locale)
+			want := format.Layout
+			if tt.wantLocal {
+				want = format.LocalLayout
+			}
+
+			if got != want {
+				t.Errorf("got %v, want %v", got, want)
+			}
+		})
+	}
+}
+
+func TestFormat_SelectRegions(t *testing.T) {
+	tests := []struct {
+		countryCode string
+		locale      string
+		wantLocal   bool
+	}{
+		// China ("zh").
+		{"CN", "en", false},
+		{"CN", "ja", false},
+		{"CN", "zh-Latn", false},
+		{"CN", "zh", true},
+		{"CN", "zh-Hant", true},
+		// Hong Kong ("zh-Hant").
+		{"HK", "en", false},
+		{"HK", "ja", false},
+		{"HK", "zh-Latn", false},
+		{"HK", "zh", true},
+		{"HK", "zh-Hant", true},
+		// Serbia (no local regions defined).
+		{"RS", "en", false},
+	}
+
+	for _, tt := range tests {
+		t.Run("", func(t *testing.T) {
+			format := address.GetFormat(tt.countryCode)
+			locale := address.NewLocale(tt.locale)
+			got := format.SelectRegions(locale)
+			want := format.Regions
+			if tt.wantLocal {
+				want = format.LocalRegions
+			}
+			if !reflect.DeepEqual(got, want) {
+				t.Errorf("got %v, want %v", got, want)
+			}
+		})
+	}
+}
+
 func TestCheckCountryCode(t *testing.T) {
 	tests := []struct {
 		countryCode string