More robust for invalid data

src/data/List.js

@@ -296,7 +296,7 @@ define(function (require) {
     };
 
     /**
-     * Get value
+     * Get value. Return NaN if idx is out of range.
      * @param {string} dim Dim must be concrete name.
      * @param {number} idx
      * @param {boolean} stack
@@ -306,6 +306,11 @@ define(function (require) {
         var storage = this._storage;
         var dataIndex = this.indices[idx];
 
+        // If value not exists
+        if (dataIndex == null) {
+            return NaN;
+        }
+
         var value = storage[dim] && storage[dim][dataIndex];
         // FIXME ordinal data type is not stackable
         if (stack) {

src/util/number.js

@@ -94,6 +94,9 @@ define(function (require) {
      * @param {number} val
      */
     number.getPrecision = function (val) {
+        if (isNaN(val)) {
+            return 0;
+        }
         // It is much faster than methods converting number to string as follows
         //      var tmp = val.toString();
         //      return tmp.length - 1 - tmp.indexOf('.');