Reduce i18n.load side effects

closes #7184

Changelog.md

@@ -2,6 +2,7 @@
 
 ## Refactor
 * Use string-direction gem for rtl detection [#7181](https://github.com/diaspora/diaspora/pull/7181)
+* Reduce i18n.load side effects [#7184](https://github.com/diaspora/diaspora/pull/7184)
 
 ## Bug fixes
 * Fix fetching comments after fetching likes [#7167](https://github.com/diaspora/diaspora/pull/7167)

app/assets/javascripts/helpers/i18n.js

@@ -18,7 +18,7 @@ Diaspora.I18n = {
   },
 
   updateLocale: function(locale, data) {
-    locale.data = $.extend(locale.data, data);
+    locale.data = $.extend({}, locale.data, data);
 
     var rule = locale.data.pluralization_rule;
     if (typeof rule !== "undefined") {

spec/javascripts/helpers/i18n_spec.js

@@ -45,6 +45,28 @@ describe("Diaspora.I18n", function() {
 
       expect(Diaspora.I18n.locale.data).toEqual(extended);
     });
+
+    it("overrides existing translations", function() {
+      var oldLocale = {name: "Bob"};
+      var newLocale = {name: "Alice"};
+      Diaspora.I18n.load(oldLocale, "en");
+      expect(Diaspora.I18n.locale.data.name).toBe("Bob");
+      Diaspora.I18n.load(newLocale, "en");
+      expect(Diaspora.I18n.locale.data.name).toBe("Alice");
+
+      Diaspora.I18n.reset(oldLocale);
+      expect(Diaspora.I18n.locale.data.name).toBe("Bob");
+      Diaspora.I18n.load(newLocale, "en");
+      expect(Diaspora.I18n.locale.data.name).toBe("Alice");
+    });
+
+    it("doesn't change locale objects given in ealier calls", function() {
+      var oldLocale = {name: "Bob"};
+      var newLocale = {name: "Alice"};
+      Diaspora.I18n.reset(oldLocale);
+      Diaspora.I18n.load(newLocale, "en");
+      expect(oldLocale.name).toBe("Bob");
+    });
   });
 
   describe("::t", function() {