catching circular references when stringifying objects, fixes #4

bower.json

@@ -1,7 +1,7 @@
 {
   "name": "lazy-ass",
   "main": "index.js",
-  "version": "0.5.2",
+  "version": "0.5.3",
   "homepage": "https://github.com/bahmutov/lazy-ass",
   "license": "MIT",
   "ignore": [

index.js

@@ -31,7 +31,13 @@
       if (arg instanceof Error) {
         return total + arg.name + ' ' + arg.message;
       }
-      return total + JSON.stringify(arg, null, 2);
+      var argString;
+      try {
+        argString = JSON.stringify(arg, null, 2);
+      } catch (err) {
+        argString = '[cannot stringify arg ' + k + ']';
+      }
+      return total + argString;
     }, '');
     return msg;
   }

package.json

@@ -1,7 +1,7 @@
 {
   "name": "lazy-ass",
   "description": "Lazy assertions without performance penalty",
-  "version": "0.5.2",
+  "version": "0.5.3",
   "author": "Gleb Bahmutov <gleb.bahmutov@gmail.com>",
   "bugs": {
     "url": "https://github.com/bahmutov/lazy-ass/issues"

test/lazy-ass.spec.js

@@ -164,6 +164,22 @@
       });
     });
 
+    describe('serializes circular objects', function () {
+      var foo = {
+        bar: 'bar'
+      };
+      foo.foo = foo;
+
+      it('can handle circular object', function () {
+        var msg = 'foo has circular reference';
+        expect(function () {
+          lazyAss(false, msg, foo);
+        }).to.throwException(function (err) {
+          expect(err.message).to.contain(msg);
+        });
+      });
+    });
+
     describe('serialize arguments', function () {
       function foo() {
         la(false, arguments);