add the ability to pass props to context.throw

lib/context.js

@@ -63,10 +63,11 @@ var proto = module.exports = {
    *
    * @param {String|Number|Error} err, msg or status
    * @param {String|Number|Error} err, msg or status
+   * @param {Object} [props]
    * @api public
    */
 
-  throw: function(msg, status){
+  throw: function(msg, status, props){
     if ('number' == typeof msg) {
       var tmp = msg;
       msg = status || http.STATUS_CODES[tmp];
@@ -76,6 +77,11 @@ var proto = module.exports = {
     var err = msg instanceof Error ? msg : new Error(msg);
     err.status = status || err.status || 500;
     err.expose = 'number' == typeof err.status && http.STATUS_CODES[err.status] && err.status < 500;
+
+    if (props) {
+      for (var key in props) err[key] = props[key];
+    }
+
     throw err;
   },
 

test/context/throw.js

@@ -124,3 +124,19 @@ describe('ctx.throw(status)', function(){
     })
   })
 })
+
+describe('ctx.throw(status, msg, props)', function(){
+  it('should mixin props', function(done){
+    var ctx = context();
+
+    try {
+      ctx.throw(400, 'msg', { prop: true });
+    } catch (err) {
+      assert('msg' == err.message);
+      assert(400 == err.status);
+      assert(true === err.expose);
+      assert(true === err.prop);
+      done();
+    }
+  })
+})