Support encoding of NaN, infinity and negative infinity.

pkg/compiler/lib/src/serialization/serialization.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.serialization;
 
 import '../common.dart';
 import '../common/resolution.dart';
 import '../constants/expressions.dart';
 import '../dart_types.dart';
@@ skipping 522 matching lines @@
       throw new StateError("Ints value '$key' not found in $_map.");
     }
     return list;
   }
 
   /// Returns the [double] value associated with [key] in the decoded object.
   ///
   /// If no value is associated with [key], then if [isOptional] is `true`,
   /// [defaultValue] is returned, otherwise an exception is thrown.
   double getDouble(K key, {bool isOptional: false, double defaultValue}) {
-    double value = _map[_getKeyValue(key)];
+    var value = _map[_getKeyValue(key)];
     if (value == null) {
       if (isOptional || defaultValue != null) {
         return defaultValue;
       }
       throw new StateError("double value '$key' not found in $_map.");
     }
+    // Support alternative encoding of NaN and +/- infinity for JSON.
+    if (value == 'NaN') {
+      return double.NAN;
+    } else if (value == '-Infinity') {
+      return double.NEGATIVE_INFINITY;
+    } else if (value == 'Infinity') {
+      return double.INFINITY;
+    }
     return value;
   }
 
   /// Returns an [ObjectDecoder] for the map value associated with [key] in the
   /// decoded object.
   ///
   /// If no value is associated with [key], then if [isOptional] is `true`,
   /// `null` is returned, otherwise an exception is thrown.
   ObjectDecoder getObject(K key, {bool isOptional: false}) {
     Map map = _map[_getKeyValue(key)];
@@ skipping 569 matching lines @@
 
   /// Returns the value used to store [key] as a property in the encoding an
   /// [ObjectValue].
   ///
   /// Different encodings have different restrictions and capabilities as how
   /// to store a [Key] value. For instance: A JSON encoding needs to convert
   /// [Key] to a [String] to store it in a JSON object; a Dart encoding can
   /// choose to store a [Key] as an [int] or as the [Key] itself.
   getObjectPropertyValue(Key key);
 }