From 93967bc8d6d42c01ae83be86e70c5ed315b8faee Mon Sep 17 00:00:00 2001
From: Michael James <mjames@urbn.com>
Date: Fri, 16 Oct 2020 17:51:14 -0400
Subject: [PATCH 1/2] Check existence of module parent in isRegistered (fix
 #1850)

---
 src/module/module-collection.js            |  6 +++++-
 test/unit/module/module-collection.spec.js | 14 ++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/module/module-collection.js b/src/module/module-collection.js
index 095872882..75e641fce 100644
--- a/src/module/module-collection.js
+++ b/src/module/module-collection.js
@@ -72,7 +72,11 @@ export default class ModuleCollection {
     const parent = this.get(path.slice(0, -1))
     const key = path[path.length - 1]
 
-    return parent.hasChild(key)
+    if (parent) {
+      return parent.hasChild(key)
+    }
+
+    return false
   }
 }
 
diff --git a/test/unit/module/module-collection.spec.js b/test/unit/module/module-collection.spec.js
index 3e8081ce3..85298c086 100644
--- a/test/unit/module/module-collection.spec.js
+++ b/test/unit/module/module-collection.spec.js
@@ -100,4 +100,18 @@ describe('ModuleCollection', () => {
     collection.unregister(['a'])
     expect(spy).toHaveBeenCalled()
   })
+
+  it('isRegistered', () => {
+    const collection = new ModuleCollection({})
+    collection.register(['a'], {
+      state: { value: true }
+    })
+    collection.register(['a', 'b'], {
+      state: { value: false }
+    })
+    expect(collection.isRegistered(['a'])).toBe(true)
+    expect(collection.isRegistered(['a', 'b'])).toBe(true)
+    expect(collection.isRegistered(['c'])).toBe(false)
+    expect(collection.isRegistered(['c', 'd'])).toBe(false)
+  })
 })

From 581e2ac0ad85f1177f7a0a9cc9af769e3fb553ae Mon Sep 17 00:00:00 2001
From: Kia Ishii <kia.king.08@gmail.com>
Date: Thu, 5 Nov 2020 17:47:45 +0900
Subject: [PATCH 2/2] test: add more tests

---
 test/unit/module/module-collection.spec.js | 31 ++++++++++++----------
 test/unit/modules.spec.js                  | 12 +++++++++
 2 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/test/unit/module/module-collection.spec.js b/test/unit/module/module-collection.spec.js
index 85298c086..514965cab 100644
--- a/test/unit/module/module-collection.spec.js
+++ b/test/unit/module/module-collection.spec.js
@@ -81,6 +81,23 @@ describe('ModuleCollection', () => {
     expect(collection.get(['a'])).toBe(undefined)
   })
 
+  it('isRegistered', () => {
+    const collection = new ModuleCollection({})
+
+    collection.register(['a'], {
+      state: { value: true }
+    })
+
+    collection.register(['a', 'b'], {
+      state: { value: false }
+    })
+
+    expect(collection.isRegistered(['a'])).toBe(true)
+    expect(collection.isRegistered(['a', 'b'])).toBe(true)
+    expect(collection.isRegistered(['c'])).toBe(false)
+    expect(collection.isRegistered(['c', 'd'])).toBe(false)
+  })
+
   it('does not unregister initial modules', () => {
     const collection = new ModuleCollection({
       modules: {
@@ -100,18 +117,4 @@ describe('ModuleCollection', () => {
     collection.unregister(['a'])
     expect(spy).toHaveBeenCalled()
   })
-
-  it('isRegistered', () => {
-    const collection = new ModuleCollection({})
-    collection.register(['a'], {
-      state: { value: true }
-    })
-    collection.register(['a', 'b'], {
-      state: { value: false }
-    })
-    expect(collection.isRegistered(['a'])).toBe(true)
-    expect(collection.isRegistered(['a', 'b'])).toBe(true)
-    expect(collection.isRegistered(['c'])).toBe(false)
-    expect(collection.isRegistered(['c', 'd'])).toBe(false)
-  })
 })
diff --git a/test/unit/modules.spec.js b/test/unit/modules.spec.js
index 9ae47c862..8f11842d8 100644
--- a/test/unit/modules.spec.js
+++ b/test/unit/modules.spec.js
@@ -91,6 +91,18 @@ describe('Modules', () => {
       expect(store.hasModule('bonjour')).toBe(false)
     })
 
+    it('dynamic module existance test with nested modules', () => {
+      const store = new Vuex.Store({})
+
+      store.registerModule('a', {})
+      store.registerModule(['a', 'b'], {})
+
+      expect(store.hasModule(['a'])).toBe(true)
+      expect(store.hasModule(['a', 'b'])).toBe(true)
+      expect(store.hasModule(['c'])).toBe(false)
+      expect(store.hasModule(['c', 'd'])).toBe(false)
+    })
+
     it('dynamic module registration preserving hydration', () => {
       const store = new Vuex.Store({})
       store.replaceState({ a: { foo: 'state' }})