feat: modify the return of diff function

src/diff.js

@@ -1,6 +1,13 @@
-import perform from './perform'
+import getDetails from './getDetails'
 import wrap from './wrap'
 
 export default function diff (original, derived) {
-  return perform(wrap(original), wrap(derived))
+  const details = getDetails(wrap(original), wrap(derived))
+
+  return {
+    hasChanged: !!details.length || (
+      typeof original !== 'object' && typeof derived !== 'object' && original !== derived
+    ),
+    details
+  }
 }

src/perform.js → src/getDetails.js

@@ -4,15 +4,15 @@ import getDeletion from './getDeletion'
 import getProperties from './getProperties'
 import heap from './heap'
 
-export default function perform (originalWrapped, derivedWrapped) {
+export default function getDetails (originalWrapped, derivedWrapped) {
   const properties = getProperties(originalWrapped.value, derivedWrapped.value)
 
   return properties.reduce((result, property) => {
     const heaped = [originalWrapped, derivedWrapped].map(wrapped => heap(wrapped, property))
 
     return [...result, ...(
       heaped.every(item => item && item.type === 'object')
-        ? perform(...heaped)
+        ? getDetails(...heaped)
         : [getChange(...heaped) || getDeletion(...heaped) || getDefinition(...heaped)].filter(Boolean)
     )]
   }, [])

test/diff.spec.js

@@ -1,31 +1,71 @@
-jest.mock('../src/perform')
-jest.mock('../src/wrap')
-
 import diff from '../src/diff'
-import perform from '../src/perform'
-import wrap from '../src/wrap'
 
 describe('diff', () => {
-  afterEach(() => {
-    wrap.mockClear()
-    perform.mockClear()
-  })
+  describe('when both parameters are non-objects', () => {
+    describe('and are different', () => {
+      const original = 'value'
+      const derived = 'new value'
+
+      it('returns "hasChanged" as "true" and "details" as empty array', () => {
+        const result = diff(original, derived)
+
+        expect(result).toEqual({
+          hasChanged: true,
+          details: expect.any(Array)
+        })
+
+        expect(result.details.length).toBe(0)
+      })
+    })
+
+    describe('and are equal', () => {
+      const original = 'value'
+      const derived = original
+
+      it('returns "hasChanged" as "false" and "details" as empty array', () => {
+        const result = diff(original, derived)
+
+        expect(result).toEqual({
+          hasChanged: false,
+          details: expect.any(Array)
+        })
+
+        expect(result.details.length).toBe(0)
+      })
+    })
+
+    describe('when one of the parameters is an object', () => {
+      describe('and both are different', () => {
+        const original = { attribute: 'value' }
+        const derived = { attribute: 'new value' }
+
+        it('returns "hasChanged" as "true" and "details" as non-empty array', () => {
+          const result = diff(original, derived)
+
+          expect(result).toEqual({
+            hasChanged: true,
+            details: expect.any(Array)
+          })
+
+          expect(result.details.length).not.toBe(0)
+        })
+      })
 
-  it('returns the result of calling "perform"', () => {
-    const original = {}
-    const derived = {}
-    const originalWrapped = {}
-    const derivedWrapped = {}
-    const result = []
+      describe('and both are equal', () => {
+        const original = { attribute: 'value' }
+        const derived = original
 
-    wrap
-      .mockReturnValueOnce(originalWrapped)
-      .mockReturnValueOnce(derivedWrapped)
+        it('returns "hasChanged" as "false" and "details" as empty array', () => {
+          const result = diff(original, derived)
 
-    perform.mockReturnValue(result)
+          expect(result).toEqual({
+            hasChanged: false,
+            details: expect.any(Array)
+          })
 
-    expect(diff(original, derived)).toBe(result)
-    expect(wrap.mock.calls).toEqual([[original], [derived]])
-    expect(perform).toBeCalledWith(originalWrapped, derivedWrapped)
+          expect(result.details.length).toBe(0)
+        })
+      })
+    })
   })
 })

test/perform.spec.js → test/getDetails.spec.js

@@ -1,7 +1,7 @@
 import wrap from '../src/wrap'
-import perform from '../src/perform'
+import getDetails from '../src/getDetails'
 
-describe('perform', () => {
+describe('getDetails', () => {
   const examples = [
     /*  0 */ [{}, {}],
     /*  1 */ [{ property: 'value' }, { property: 'value' }],
@@ -420,7 +420,7 @@ describe('perform', () => {
 
   it('returns a list of differences between two objects', () => {
     examples.forEach((example, i) => {
-      expect(perform(...example)).toEqual(expectations[i])
+      expect(getDetails(...example)).toEqual(expectations[i])
     })
   })
 })