Adding DateTimeFormat class to i18n API.

src/extensions/experimental/i18n.js

Index: src/extensions/experimental/i18n.js
===================================================================
--- src/extensions/experimental/i18n.js	(revision 7878)
+++ src/extensions/experimental/i18n.js	(working copy)
@@ -131,13 +131,93 @@
 /**
  * Creates new Collator based on current locale.
  * @param {Object} - collation flags. See constructor.
- * @returns {Object} - new v8BreakIterator object.
+ * @returns {Object} - new Collator object.
  */
 v8Locale.prototype.createCollator = function(settings) {
   return new v8Locale.Collator(this, settings);
 };
 
 /**
+ * DateTimeFormat class implements locale-aware date and time formatting.
+ * @param {Object} locale - locale object to pass to formatter.
+ * @param {Object} settings - formatting flags:
+ *   - skeleton
+ *   - dateType
+ *   - timeType
+ *   - calendar
+ * @constructor
+ */
+v8Locale.DateTimeFormat = function(locale, settings) {
+  native function NativeJSDateTimeFormat();
+
+  settings = v8Locale.createSettingsOrDefault_(settings, {});
+
+  var cleanSettings = {};
+  if (settings.hasOwnProperty('skeleton')) {
+    cleanSettings['skeleton'] = settings['skeleton'];
+  } else {
+    cleanSettings = {};
+    if (settings.hasOwnProperty('dateType')) {
+      var dt = settings['dateType'].toLowerCase();
+      if (dt !== 'short' && dt !== 'long') dt = 'short';
+      cleanSettings['dateType'] = dt;
+    }
+
+    if (settings.hasOwnProperty('timeType')) {
+      var tt = settings['timeType'].toLowerCase();
+      if (tt !== 'short' && tt !== 'medium') tt = 'short';
+      cleanSettings['timeType'] = tt;
+    }
+  }
+
+  // Default is to show short date and time.
+  if (!cleanSettings.hasOwnProperty('skeleton') &&
+      !cleanSettings.hasOwnProperty('dateType') &&
+      !cleanSettings.hasOwnProperty('timeType')) {
+    cleanSettings = {'dateType': 'short',
+                     'timeType': 'short'};
+  }
+
+  locale = v8Locale.createLocaleOrDefault_(locale);
+  var formatter = NativeJSDateTimeFormat(locale.__icuLocaleID__, cleanSettings);
+
+  // NativeJSDateTimeFormat creates formatter.options for us, we just need
+  // to append actual settings to it.
+  for (key in cleanSettings) {
+    formatter.options[key] = cleanSettings[key];
+  }
+
+  /**
+   * Clones existing date time format with possible overrides for some
+   * of the options.
+   * @param {!Object} overrideSettings - overrides for current format settings.
+   * @returns {Object} - new DateTimeFormat object.
+   */
+  formatter.derive = function(overrideSettings) {
+    // To remove a setting user can specify undefined as its value. We'll remove
+    // it from the map in that case.
+    for (var prop in overrideSettings) {
+      if (settings.hasOwnProperty(prop) && !overrideSettings[prop]) {
+        delete settings[prop];
+      }
+    }
+    return new v8Locale.DateTimeFormat(
+        locale, v8Locale.createSettingsOrDefault_(overrideSettings, settings));
+  };
+
+  return formatter;
+};
+
+/**
+ * Creates new DateTimeFormat based on current locale.
+ * @param {Object} - formatting flags. See constructor.
+ * @returns {Object} - new DateTimeFormat object.
+ */
+v8Locale.prototype.createDateTimeFormat = function(settings) {
+  return new v8Locale.DateTimeFormat(this, settings);
+};
+
+/**
  * Merges user settings and defaults.
  * Settings that are not of object type are rejected.
  * Actual property values are not validated, but whitespace is trimmed if they
@@ -155,11 +235,17 @@
       settings[key] = defaults[key];
     }
   }
-  // Clean up values, like trimming whitespace.
+  // Clean up settings.
   for (var key in settings) {
+    // Trim whitespace.
     if (typeof(settings[key]) === "string") {
       settings[key] = settings[key].trim();
     }
+    // Remove all properties that are set to undefined/null. This allows
+    // derive method to remove a setting we don't need anymore.
+    if (!settings[key]) {
+      delete settings[key];
+    }
   }
 
   return settings;