Add expected types to oneOfType warning (#9)

Adds data object to returned error in checker so that the expected types can be accessed from within oneOfType check. Also, updates the tests slightly.

Fixes: #9

__tests__/PropTypesDevelopmentReact15.js

@@ -913,7 +913,7 @@ describe('PropTypesDevelopmentReact15', () => {
       typeCheckFail(
         PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
         [],
-        'Invalid prop `testProp` supplied to `testComponent`.',
+        'Invalid prop `testProp` supplied to `testComponent`, expected one of type [string, number].',
       );
 
       const checker = PropTypes.oneOfType([

__tests__/PropTypesDevelopmentStandalone-test.js

@@ -915,7 +915,7 @@ describe('PropTypesDevelopmentStandalone', () => {
       typeCheckFail(
         PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
         [],
-        'Invalid prop `testProp` supplied to `testComponent`.',
+        'Invalid prop `testProp` supplied to `testComponent`, expected one of type [string, number].',
       );
 
       const checker = PropTypes.oneOfType([

factoryWithTypeCheckers.js

@@ -157,8 +157,9 @@ module.exports = function(isValidElement, throwOnDirectAccess) {
    * is prohibitively expensive if they are created too often, such as what
    * happens in oneOfType() for any type before the one that matched.
    */
-  function PropTypeError(message) {
+  function PropTypeError(message, data) {
     this.message = message;
+    this.data = (typeof data == 'object') ? data: {};
     this.stack = '';
   }
   // Make `instanceof Error` still work for returned errors.
@@ -232,7 +233,10 @@ module.exports = function(isValidElement, throwOnDirectAccess) {
         // 'of type `object`'.
         var preciseType = getPreciseType(propValue);
 
-        return new PropTypeError('Invalid ' + location + ' `' + propFullName + '` of type ' + ('`' + preciseType + '` supplied to `' + componentName + '`, expected ') + ('`' + expectedType + '`.'));
+        return new PropTypeError(
+          'Invalid ' + location + ' `' + propFullName + '` of type ' + ('`' + preciseType + '` supplied to `' + componentName + '`, expected ') + ('`' + expectedType + '`.'),
+          {expectedType: expectedType}
+        );
       }
       return null;
     }
@@ -349,14 +353,18 @@ module.exports = function(isValidElement, throwOnDirectAccess) {
     }
 
     function validate(props, propName, componentName, location, propFullName) {
+      var expectedTypes = [];
       for (var i = 0; i < arrayOfTypeCheckers.length; i++) {
         var checker = arrayOfTypeCheckers[i];
-        if (checker(props, propName, componentName, location, propFullName, ReactPropTypesSecret) == null) {
+        var checkerResult = checker(props, propName, componentName, location, propFullName, ReactPropTypesSecret);
+        if (checkerResult == null) {
           return null;
+        } else if (checkerResult.data.hasOwnProperty('expectedType')) {
+          expectedTypes.push(checkerResult.data.expectedType);
         }
       }
-
-      return new PropTypeError('Invalid ' + location + ' `' + propFullName + '` supplied to ' + ('`' + componentName + '`.'));
+      var expectedTypesMessage = (expectedTypes.length > 0) ? ', expected one of type [' + expectedTypes.join(', ') + ']': '';
+      return new PropTypeError('Invalid ' + location + ' `' + propFullName + '` supplied to ' + ('`' + componentName + '`' + expectedTypesMessage + '.'));
     }
     return createChainableTypeChecker(validate);
   }