Fix diffs of circular structures (close mochajs#1198, fix mochajs#1179)

lib/reporters/base.js

@@ -188,8 +188,8 @@ exports.list = function(failures){
     // explicitly show diff
     if (err.showDiff && sameType(actual, expected)) {
       escape = false;
-      err.actual = actual = stringify(canonicalize(actual));
-      err.expected = expected = stringify(canonicalize(expected));
+      err.actual = actual = utils.stringify(actual);
+      err.expected = expected = utils.stringify(expected);
     }
 
     // actual / expected diff
@@ -453,53 +453,6 @@ function colorLines(name, str) {
   }).join('\n');
 }
 
-/**
- * Stringify `obj`.
- *
- * @param {Object} obj
- * @return {String}
- * @api private
- */
-
-function stringify(obj) {
-  if (obj instanceof RegExp) return obj.toString();
-  return JSON.stringify(obj, null, 2);
-}
-
-/**
- * Return a new object that has the keys in sorted order.
- * @param {Object} obj
- * @return {Object}
- * @api private
- */
-
- function canonicalize(obj, stack) {
-   stack = stack || [];
-
-   if (utils.indexOf(stack, obj) !== -1) return obj;
-
-   var canonicalizedObj;
-
-   if ('[object Array]' == {}.toString.call(obj)) {
-     stack.push(obj);
-     canonicalizedObj = utils.map(obj, function(item) {
-       return canonicalize(item, stack);
-     });
-     stack.pop();
-   } else if (typeof obj === 'object' && obj !== null) {
-     stack.push(obj);
-     canonicalizedObj = {};
-     utils.forEach(utils.keys(obj).sort(), function(key) {
-       canonicalizedObj[key] = canonicalize(obj[key], stack);
-     });
-     stack.pop();
-   } else {
-     canonicalizedObj = obj;
-   }
-
-   return canonicalizedObj;
- }
-
 /**
  * Check that a / b have the same type.
  *
@@ -514,4 +467,3 @@ function sameType(a, b) {
   b = Object.prototype.toString.call(b);
   return a == b;
 }
-

lib/utils.js

@@ -300,3 +300,51 @@ exports.highlightTags = function(name) {
     code[i].innerHTML = highlight(code[i].innerHTML);
   }
 };
+
+
+/**
+ * Stringify `obj`.
+ *
+ * @param {Object} obj
+ * @return {String}
+ * @api private
+ */
+
+exports.stringify = function(obj) {
+  if (obj instanceof RegExp) return obj.toString();
+  return JSON.stringify(exports.canonicalize(obj), null, 2);
+}
+
+/**
+ * Return a new object that has the keys in sorted order.
+ * @param {Object} obj
+ * @return {Object}
+ * @api private
+ */
+
+exports.canonicalize = function(obj, stack) {
+   stack = stack || [];
+
+   if (exports.indexOf(stack, obj) !== -1) return '[Circular]';
+
+   var canonicalizedObj;
+
+   if ({}.toString.call(obj) === '[object Array]') {
+     stack.push(obj);
+     canonicalizedObj = exports.map(obj, function(item) {
+       return exports.canonicalize(item, stack);
+     });
+     stack.pop();
+   } else if (typeof obj === 'object' && obj !== null) {
+     stack.push(obj);
+     canonicalizedObj = {};
+     exports.forEach(exports.keys(obj).sort(), function(key) {
+       canonicalizedObj[key] = exports.canonicalize(obj[key], stack);
+     });
+     stack.pop();
+   } else {
+     canonicalizedObj = obj;
+   }
+
+   return canonicalizedObj;
+ }

test/acceptance/utils.js

@@ -70,4 +70,20 @@ describe('lib/utils', function () {
       utils.clean(fn).should.equal("foo()");
     });
   });
-});
+
+  describe('stringify', function(){
+    it('should canoncalize the object', function(){
+      var travis = { name: 'travis', age: 24 };
+      var travis2 = { age: 24, name: 'travis' };
+
+      utils.stringify(travis).should.equal(utils.stringify(travis2));
+    });
+
+    it('should handle circular structures', function(){
+      var travis = { name: 'travis' };
+      travis.whoami = travis;
+
+      utils.stringify(travis).should.equal('{\n  "name": "travis",\n  "whoami": "[Circular]"\n}');
+    });
+  });
+});