rename isDuplicateKey

Author: hunterliu1003

lib/Plugin.js

@@ -9,13 +9,13 @@ const defaultOptions = {
 const Plugin = () => ({
   install(Vue, options) {
     const _options = Object.assign({}, defaultOptions, options)
-    const isDuplicateCmd = Vue.prototype[_options.key]
+    const isDuplicateKey = Vue.prototype[_options.key]
     const isDuplicateComponent = Vue.options.components[_options.componentName]
 
     if (isDuplicateComponent) {
-      console.warn(isDuplicateCmd ? DUPLICATE_PLUGIN_COMPONENT : DUPLICATE_COMPONENT)
+      console.warn(isDuplicateKey ? DUPLICATE_PLUGIN_COMPONENT : DUPLICATE_COMPONENT)
     } else {
-      if (!isDuplicateCmd) {
+      if (!isDuplicateKey) {
         bindPrototype(Vue, _options)
       }
       registComponent(Vue, _options)