Allow overriding the locale for individual translations

addon/services/i18n.js

@@ -17,22 +17,21 @@ export default Parent.extend(Evented, {
   // A list of found locales.
   locales: computed(getLocales),
 
+  // @public
+  // Whether to allow overriding the locale for individual translations.
+  allowLocaleOverride: undefined,
+
   // @public
   //
   // Returns the translation `key` interpolated with `data`
   // in the current `locale`.
   t(key, data = {}) {
-    Ember.deprecate('locale is a reserved attribute', data['locale'] === undefined, {
-      id: 'ember-i18n.reserve-locale',
-      until: '5.0.0'
-    });
-
     Ember.deprecate('htmlSafe is a reserved attribute', data['htmlSafe'] === undefined, {
       id: 'ember-i18n.reserve-htmlSafe',
       until: '5.0.0'
     });
 
-    const locale = this.get('_locale');
+    const locale = this._getLocaleWithOverride(data);
     assert("I18n: Cannot translate when locale is null", locale);
     const count = get(data, 'count');
 
@@ -42,15 +41,15 @@ export default Parent.extend(Evented, {
     const template = locale.getCompiledTemplate(defaults, count);
 
     if (template._isMissing) {
-      this.trigger('missing', this.get('locale'), key, data);
+      this.trigger('missing', locale.id, key, data);
     }
 
     return template(data);
   },
 
   // @public
   exists(key, data = {}) {
-    const locale = this.get('_locale');
+    const locale = this._getLocaleWithOverride(data);
     assert("I18n: Cannot check existance when locale is null", locale);
     const count = get(data, 'count');
 
@@ -83,6 +82,10 @@ export default Parent.extend(Evented, {
       }
       this.set('locale', defaultLocale);
     }
+
+    if (this.get('allowLocaleOverride') == null) {
+      this.set('allowLocaleOverride', (ENV.i18n || {}).allowLocaleOverride);
+    }
   }),
 
   // @private
@@ -96,5 +99,24 @@ export default Parent.extend(Evented, {
     const locale = this.get('locale');
 
     return locale ? new Locale(this.get('locale'), getOwner(this)) : null;
-  })
+  }),
+
+  // @private
+  // Retrieves the current locale, allowing it to be overridden by a `locale`
+  // option in the translation data if `allowLocaleOverride` is enabled.
+  _getLocaleWithOverride: function(data) {
+    let locale = this.get('_locale');
+
+    if (data.locale && this.get('allowLocaleOverride') !== false) {
+      Ember.warn(
+        'Specifying an interpolation key named `locale` now overrides the target locale for translation. To silence this warning, set ENV.i18n.allowLocaleOverride to true. To disable this behavior and treat `locale` as a normal interpolation key, set ENV.i18n.allowLocaleOverride to false.',
+        (this.get('allowLocaleOverride') !== undefined),
+        { id: 'ember-i18n.locale-override' }
+      );
+      locale = new Locale(data.locale, getOwner(this));
+      delete data.locale;
+    }
+
+    return locale;
+  }
 });

tests/acceptance/t-helper-test.js

@@ -50,3 +50,7 @@ test('updates when the locale changes', function(assert) {
     assert.textIs('.no-interpolations', 'texto sin interpolaciones');
   });
 });
+
+test('can override the target locale', function(assert) {
+  assert.textIs('.locale-override', 'texto sin interpolaciones');
+});

tests/dummy/app/locales/en/translations.js

@@ -3,7 +3,8 @@ export default {
   'no.interpolations.either': 'another text without interpolations',
 
   'with': {
-    interpolations: 'Clicks: {{clicks}}'
+    interpolations: 'Clicks: {{clicks}}',
+    'locale.interpolation': 'Locale: {{locale}}'
   },
 
   'pluralized.translation': {

tests/dummy/app/templates/index.hbs

@@ -21,3 +21,7 @@
 <section>
   <button class='switch-to-es' {{action "switchLocale" "es"}}>Switch to Spanish</button>
 </section>
+
+<section>
+  <span class='locale-override'>{{t "no.interpolations" locale="es"}}</span>
+</section>

tests/unit/i18n-exists-test.js

@@ -41,3 +41,9 @@ test('non-existing translations when checked twice do not exist', function (asse
   assert.equal(i18n.t('not.existing'), 'Missing translation: not.existing');
   assert.equal(i18n.exists('not.existing'), false);
 });
+
+test('allows overriding the locale', function(assert) {
+  const i18n = this.subject({ locale: 'en' });
+
+  assert.equal(i18n.exists('no.interpolations.either', { locale: 'es' }), false);
+});

tests/unit/i18n-t-test.js

@@ -1,13 +1,23 @@
 import Ember from 'ember';
 import { moduleFor, test } from 'ember-qunit';
 
-const { run, deprecate:originalDeprecate } = Ember;
+const { run, deprecate:originalDeprecate, warn:originalWarn } = Ember;
+const warnings = Ember.A();
 
 moduleFor('service:i18n', 'I18nService#t', {
   integration: true,
 
+  beforeEach() {
+    Ember.warn = function(message, test, options) {
+      if (!test) { warnings.pushObject(message); }
+      originalWarn(message, test, options);
+    };
+  },
+
   afterEach() {
     Ember.deprecate = originalDeprecate;
+    Ember.warn = originalWarn;
+    warnings.clear();
   }
 });
 
@@ -40,7 +50,7 @@ test('returns "missing translation" translations', function(assert) {
   assert.equal('Missing translation: not.yet.translated', result);
 });
 
-test('warns on the presence of htmlSafe and locale', function(assert) {
+test('warns on the presence of htmlSafe', function(assert) {
   const service = this.subject();
   let deprecations = 0;
 
@@ -49,20 +59,17 @@ test('warns on the presence of htmlSafe and locale', function(assert) {
 
     const { id } = options;
 
-    if (id === 'ember-i18n.reserve-htmlSafe' || id === 'ember-i18n.reserve-locale') {
+    if (id === 'ember-i18n.reserve-htmlSafe') {
       deprecations += 1;
     }
   };
 
   service.t('not.yet.translated', { htmlSafe: true });
   assert.equal(deprecations, 1);
 
-  service.t('not.yet.translated', { locale: true });
-  assert.equal(deprecations, 2);
-
   service.t('not.yet.translated');
   service.t('not.yet.translated', { some: 'other key' });
-  assert.equal(deprecations, 2);
+  assert.equal(deprecations, 1);
 });
 
 test('emits "missing" events', function(assert) {
@@ -120,3 +127,42 @@ test("check unknown locale", function(assert) {
   const result = this.subject({ locale: 'uy' }).t('not.yet.translated', {count: 2});
   assert.equal('Missing translation: not.yet.translated', result);
 });
+
+test("locale can be overridden and warns by default", function(assert) {
+  const i18n = this.subject({ locale: 'en' });
+
+  const result = i18n.t('no.interpolations', { locale: 'es' });
+  assert.equal(result, 'texto sin interpolaciones');
+  assert.equal(warnings.length, 1);
+});
+
+test("locale can be overridden and does not warn if allowLocaleOverride is true", function(assert) {
+  const i18n = this.subject({ locale: 'en', allowLocaleOverride: true });
+
+  const result = i18n.t('no.interpolations', { locale: 'es' });
+  assert.equal(result, 'texto sin interpolaciones');
+  assert.equal(warnings.length, 0);
+});
+
+test("locale can be used as an interpolation key if allowLocaleOverride is false", function(assert) {
+  const i18n = this.subject({ locale: 'en', allowLocaleOverride: false });
+
+  const result = i18n.t('with.locale.interpolation', { locale: 'es' });
+  assert.equal(result, 'Locale: es');
+  assert.equal(warnings.length, 0);
+});
+
+test('emits "missing" events with an overridden locale', function(assert) {
+  const i18n = this.subject({ locale: 'en' });
+  const calls = [];
+  function spy() { calls.push(arguments); }
+  i18n.on('missing', spy);
+
+  i18n.t('not.yet.translated', { some: 'data', locale: 'es' });
+
+  assert.equal(calls.length, 1);
+  assert.equal(calls[0].length, 3);
+  assert.equal(calls[0][0], 'es');
+  assert.equal(calls[0][1], 'not.yet.translated');
+  assert.equal(calls[0][2].some, 'data');
+});