Fix #17: Support objects with cycles

benchmark/index.js

@@ -9,6 +9,7 @@ const suite = new Benchmark.Suite;
 const equalPackages = {
   'fast-deep-equal': require('..'),
   'fast-deep-equal/es6': require('../es6'),
+  'fast-deep-equal/es6cycles': require('../es6cycles'),
   'fast-equals': require('fast-equals').deepEqual,
   'nano-equal': true,
   'shallow-equal-fuzzy': true,

build.js

@@ -5,8 +5,11 @@ var doT = require('dot');
 doT.templateSettings.strip = false;
 
 var jst = doT.compile(fs.readFileSync('./src/index.jst', 'utf8'));
-fs.writeFileSync('./index.js', jst({es6: false}));
-fs.writeFileSync('./react.js', jst({es6: false, react: true}));
+fs.writeFileSync('./index.js', jst({es6: false }));
+fs.writeFileSync('./react.js', jst({es6: false, react: true }));
 try { fs.mkdirSync('./es6'); }  catch(e) {}
-fs.writeFileSync('./es6/index.js', jst({es6: true}));
-fs.writeFileSync('./es6/react.js', jst({es6: true, react: true}));
+fs.writeFileSync('./es6/index.js', jst({es6: true }));
+fs.writeFileSync('./es6/react.js', jst({es6: true, react: true }));
+try { fs.mkdirSync('./es6cycles'); }  catch(e) {}
+fs.writeFileSync('./es6cycles/index.js', jst({es6: true, cycles: true}));
+fs.writeFileSync('./es6cycles/react.js', jst({es6: true, react: true, cycles: true }));

spec/cycle_tests.js

@@ -0,0 +1,105 @@
+'use strict';
+
+var obj1 = {a: 1, b: 2};
+var obj2 = {a: 1, b: 2};
+var obj3 = {a: 1, b: 2};
+obj1.c = obj2;
+obj2.c = obj3;
+obj3.c = obj3;
+
+var obj4 = {e: 3, f: 4};
+var obj5 = {a: 1, b: 2};
+var obj6 = {a: 1, b: 2};
+obj4.c = obj4;
+obj5.c = obj4;
+obj6.c = obj6;
+
+var obj7 = {a: 1, b: 2};
+var obj8 = {a: 1, b: 2};
+var obj9 = {a: 1, b: 2};
+obj7.c = obj7;
+obj8.c = obj9;
+obj9.c = obj8;
+
+var arr1 = [1, 2];
+var arr2 = [1, 2];
+var arr3 = [1, 2];
+arr1.push(arr2);
+arr2.push(arr3);
+arr3.push(arr3);
+
+var arr4 = [3, 4];
+var arr5 = [1, 2];
+var arr6 = [1, 2];
+arr4.push(arr4);
+arr5.push(arr4);
+arr6.push(arr6);
+
+
+module.exports = [
+  {
+    description: 'cyclic objects',
+    tests: [
+      {
+        description: 'equal cyclic objects #1',
+        value1: obj1,
+        value2: obj2,
+        equal: true
+      },
+      {
+        description: 'equal cyclic objects #2',
+        value1: obj1,
+        value2: obj3,
+        equal: true
+      },
+      {
+        description: 'equal cyclic objects #3',
+        value1: obj2,
+        value2: obj3,
+        equal: true
+      },
+      {
+        description: 'equal cyclic objects #4',
+        value1: obj7,
+        value2: obj8,
+        equal: true
+      },
+      {
+        description: 'not equal cyclic objects',
+        value1: obj5,
+        value2: obj6,
+        equal: false
+      }
+    ]
+  },
+
+  {
+    description: 'cyclic arrays',
+    tests: [
+      {
+        description: 'equal cyclic arrays #1',
+        value1: arr1,
+        value2: arr2,
+        equal: true
+      },
+      {
+        description: 'equal cyclic arrays #2',
+        value1: arr1,
+        value2: arr3,
+        equal: true
+      },
+      {
+        description: 'equal cyclic arrays #3',
+        value1: arr2,
+        value2: arr3,
+        equal: true
+      },
+      {
+        description: 'not equal cyclic arrays',
+        value1: arr5,
+        value2: arr6,
+        equal: false
+      }
+    ]
+  },
+];

spec/index.spec.js

@@ -4,11 +4,15 @@ var equal = require('..');
 var equalReact = require('../react');
 var es6equal = require('../es6');
 var es6equalReact = require('../es6/react');
+var es6cyclesEqual = require('../es6cycles');
 var assert = require('assert');
 
 testCases(equal, 'equal - standard tests', require('./tests'));
 testCases(es6equal, 'es6 equal - standard tests', require('./tests'));
 testCases(es6equal, 'es6 equal - es6 tests', require('./es6tests'));
+testCases(es6cyclesEqual, 'es6 cycles equal - standard tests', require('./tests'));
+testCases(es6cyclesEqual, 'es6 cycles equal - es6 tests', require('./es6tests'));
+testCases(es6cyclesEqual, 'es6 cycles equal - cycle tests', require('./cycle_tests'));
 
 testCases(equalReact, 'equal react - standard tests', require('./tests'));
 testCases(es6equalReact, 'es6 equal react - standard tests', require('./tests'));

src/index.jst

@@ -6,18 +6,25 @@
   var envHasBigInt64Array = typeof BigInt64Array !== 'undefined';
 {{?}}
 
-module.exports = function equal(a, b) {
+module.exports = function equal(a, b, compared) {
   if (a === b) return true;
 
   if (a && b && typeof a == 'object' && typeof b == 'object') {
     if (a.constructor !== b.constructor) return false;
 
+{{? it.es6 && it.cycles }}
+    if (!compared) compared = { a: new Set(), b: new Set() };
+    if (compared.a.has(a) && compared.b.has(b)) return true;
+    if (!compared.a.has(a)) compared.a.add(a);
+    if (!compared.b.has(b)) compared.b.add(b);
+{{?}}
+
     var length, i, keys;
     if (Array.isArray(a)) {
       length = a.length;
       if (length != b.length) return false;
       for (i = length; i-- !== 0;)
-        if (!equal(a[i], b[i])) return false;
+        if (!equal(a[i], b[i], compared)) return false;
       return true;
     }
 
@@ -27,7 +34,7 @@ module.exports = function equal(a, b) {
       for (i of a.entries())
         if (!b.has(i[0])) return false;
       for (i of a.entries())
-        if (!equal(i[1], b.get(i[0]))) return false;
+        if (!equal(i[1], b.get(i[0]), compared)) return false;
       return true;
     }
 
@@ -68,7 +75,7 @@ module.exports = function equal(a, b) {
         continue;
       }
 {{?}}
-      if (!equal(a[key], b[key])) return false;
+      if (!equal(a[key], b[key], compared)) return false;
     }
 
     return true;