fix(vuex): Refactor legacy VueX checking, closes vuejs#939 (vuejs#970)

* Change isLegacy checking strategy, adapt mutation handling to vuex 1

* ./src/backend

remove setting and related data

* Check the legacy mode before converting the payload

Author: bajzarpa

src/backend/index.js

@@ -128,10 +128,10 @@ function connect (Vue) {
 
   // vuex
   if (hook.store) {
-    initVuexBackend(hook, bridge, isLegacy)
+    initVuexBackend(hook, bridge, hook.store.commit === undefined)
   } else {
     hook.once('vuex:init', store => {
-      initVuexBackend(hook, bridge, isLegacy)
+      initVuexBackend(hook, bridge, store.commit === undefined)
     })
   }
 

src/backend/vuex.js

@@ -442,13 +442,21 @@ class VuexBackend {
         } else if (mutation.handlers) {
           this.store._committing = true
           try {
-            const payload = mutation.payload
+            let payload = mutation.payload
+
+            if (this.isLegacy && !Array.isArray(payload)) {
+              payload = [payload]
+            }
+
             if (Array.isArray(mutation.handlers)) {
-              mutation.handlers.forEach(handler => handler(payload))
+              if (this.isLegacy) {
+                mutation.handlers.forEach(handler => handler(this.store.state, ...payload))
+              } else {
+                mutation.handlers.forEach(handler => handler(payload))
+              }
             } else {
-              if (this.isLegacy || SharedData.vuex1) {
-                // Vuex 1
-                mutation.handlers(this.store.state, payload)
+              if (this.isLegacy) {
+                mutation.handlers(this.store.state, ...payload)
               } else {
                 mutation.handlers(payload)
               }

src/devtools/views/settings/GlobalPreferences.vue

@@ -91,20 +91,5 @@
         May impact performance or cause crashes
       </template>
     </VueFormField>
-
-    <VueFormField
-      title="Vuex Legacy"
-    >
-      <VueSwitch v-model="$shared.vuex1">
-        Enable compatibility mode
-      </VueSwitch>
-      <template #subtitle>
-        <VueIcon
-          icon="warning"
-          class="medium"
-        />
-        If you use Vuex 1.x, enable this option
-      </template>
-    </VueFormField>
   </div>
 </template>

src/shared-data.js

@@ -13,8 +13,7 @@ const internalSharedData = {
   recordPerf: false,
   editableProps: false,
   logDetected: true,
-  vuexAutoload: false,
-  vuex1: false
+  vuexAutoload: false
 }
 
 const persisted = [
@@ -24,8 +23,7 @@ const persisted = [
   'recordVuex',
   'editableProps',
   'logDetected',
-  'vuexAutoload',
-  'vuex1'
+  'vuexAutoload'
 ]
 
 // ---- INTERNALS ---- //