added Object key sort prior to JSON.stringify comparison (fix #5908)

src/shared/util.js

@@ -17,6 +17,23 @@ export function isTrue (v: any): boolean %checks {
 export function isFalse (v: any): boolean %checks {
   return v === false
 }
+
+/**
+ * Sorts an object by key to ensure seraialized equality
+ * by succinct key order. Guaranteed to at least return an
+ * empty object.
+ */
+export function keySort (obj: any): Object {
+  if (isObject(obj) === false) {
+    return {}
+  }
+  const sorted = {}
+  Object.keys(obj).sort().forEach(key => {
+    sorted[key] = obj[key]
+  })
+  return sorted
+}
+
 /**
  * Check if value is primitive
  */
@@ -240,7 +257,7 @@ export function looseEqual (a: mixed, b: mixed): boolean {
   const isObjectB = isObject(b)
   if (isObjectA && isObjectB) {
     try {
-      return JSON.stringify(a) === JSON.stringify(b)
+      return JSON.stringify(keySort(a)) === JSON.stringify(keySort(b))
     } catch (e) {
       // possible circular reference
       return a === b

test/unit/modules/shared/key-sort.spec.js

@@ -0,0 +1,55 @@
+import { keySort, looseEqual } from 'shared/util'
+
+describe('keySort', () => {
+  const chars = '0123456789abcdefghijklmnopqrstuvwxyz!@#$%^&*()_+./'
+  const randomWord = () => {
+    const letters = []
+    for (let cnt = 0; cnt < 10; cnt++) {
+      letters.push(chars.charAt(Math.floor(Math.random() * chars.length)))
+    }
+    return letters.join('')
+  }
+  const unsortedObject = () => {
+    const unsorted = {}
+    chars.split('').map(c => {
+      unsorted[c + '' + randomWord()] = randomWord()
+    })
+    return unsorted
+  }
+
+  it('returns Object for empty Object argument', () => {
+    expect(looseEqual(keySort({}), {})).toBe(true)
+  })
+
+  it('returns Object for Array argument', () => {
+    expect(looseEqual(keySort([]), {})).toBe(true)
+  })
+
+  it('returns Object for String argument', () => {
+    expect(looseEqual(keySort('Test String'), {})).toBe(true)
+  })
+
+  it('returns Object for Number argument', () => {
+    expect(looseEqual(keySort(Number.MAX_SAFE_INTEGER), {})).toBe(true)
+  })
+
+  it('returns Object for Undefined argument', () => {
+    expect(looseEqual(keySort(undefined), {})).toBe(true)
+  })
+
+  it('returns Object for Null argument', () => {
+    expect(looseEqual(keySort(null), {})).toBe(true)
+  })
+
+  it('Sorts an unsorted Object, which are equal', () => {
+    const unsortedTestObj = unsortedObject()
+    const sortedObject = keySort(unsortedTestObj)
+    expect(looseEqual(sortedObject, unsortedTestObj)).toBe(true)
+  })
+
+  it('does not unsort a sorted object', () => {
+    const sortedObject = keySort(unsortedObject())
+    const sortedObjectCompare = keySort(sortedObject)
+    expect(looseEqual(sortedObject, sortedObjectCompare)).toBe(true)
+  })
+})