Implements ES6 String.prototype.normalize method.

src/i18n.js

Index: src/i18n.js
diff --git a/src/i18n.js b/src/i18n.js
index 6b563a00f915a867056e73c02856f8132226d5eb..2e5485749ae766fc469c8cd52c8257fe5b57e7b4 100644
--- a/src/i18n.js
+++ b/src/i18n.js
@@ -45,6 +45,11 @@ var AVAILABLE_SERVICES = ['collator',
                           'dateformat',
                           'breakiterator'];
 
+var NORMALIZATION_FORMS = ['NFC',
+                           'NFD',
+                           'NFKC',
+                           'NFKD'];
+
 /**
  * Caches available locales for each service.
  */
@@ -1987,6 +1992,40 @@ $Object.defineProperty($String.prototype, 'localeCompare', {
 
 
 /**
+ * Unicode normalization. This method is called with one argument that
+ * specifies the normalization form.
+ * If none is specified, "NFC" is assumed.
+ * If the form is not one of "NFC", "NFD", "NFKC", or "NFKD", then throw
+ * a RangeError Exception.
+ */
+$Object.defineProperty($String.prototype, 'normalize', {
+  value: function(that) {
+    if (%_IsConstructCall()) {
+      throw new $TypeError(ORDINARY_FUNCTION_CALLED_AS_CONSTRUCTOR);

[arv (Not doing code reviews), 2014/04/10 18:20:10]

Does the spec really mandate this?

[mnita, 2014/04/10 21:20:30]

Hmmmm... Not in spec, sorry.
I will remove this whole 'if'.

+    }
+
+    CHECK_OBJECT_COERCIBLE(this, "String.prototype.normalize");
+
+    var form = $String(%_Arguments(0) || 'NFC');
+
+    var normalizationForm = NORMALIZATION_FORMS.indexOf(form);

[arv (Not doing code reviews), 2014/04/10 18:20:10]

Does this need to ensure we are calling the original indexOf?

[mnita, 2014/04/10 21:20:30]

Done.

+    if (normalizationForm === -1) {
+      throw new $RangeError('The normalization form should be one of '
+          + NORMALIZATION_FORMS.join(', ') + '.');
+    }
+
+    return %StringNormalize(this, normalizationForm);
+  },
+  writable: true,
+  configurable: true,
+  enumerable: false
+});
+%FunctionSetName($String.prototype.normalize, 'normalize');
+%FunctionRemovePrototype($String.prototype.normalize);
+%SetNativeFlag($String.prototype.normalize);
+
+
+/**
  * Formats a Number object (this) using locale and options values.
  * If locale or options are omitted, defaults are used.
  */