refactor: tiny cleanup changes (vuejs#9193)

Author: clarkdo

src/core/instance/events.js

@@ -102,16 +102,14 @@ export function eventsMixin (Vue: Class<Component>) {
       vm._events[event] = null
       return vm
     }
-    if (fn) {
-      // specific handler
-      let cb
-      let i = cbs.length
-      while (i--) {
-        cb = cbs[i]
-        if (cb === fn || cb.fn === fn) {
-          cbs.splice(i, 1)
-          break
-        }
+    // specific handler
+    let cb
+    let i = cbs.length
+    while (i--) {
+      cb = cbs[i]
+      if (cb === fn || cb.fn === fn) {
+        cbs.splice(i, 1)
+        break
       }
     }
     return vm

src/core/util/debug.js

@@ -41,7 +41,7 @@ if (process.env.NODE_ENV !== 'production') {
       ? vm.options
       : vm._isVue
         ? vm.$options || vm.constructor.options
-        : vm || {}
+        : vm
     let name = options.name || options._componentTag
     const file = options.__file
     if (!name && file) {

src/server/template-renderer/index.js

@@ -207,7 +207,7 @@ export default class TemplateRenderer {
     if (this.clientManifest) {
       const initial = this.preloadFiles.filter(({ file }) => isJS(file))
       const async = (this.getUsedAsyncFiles(context) || []).filter(({ file }) => isJS(file))
-      const needed = [initial[0]].concat(async || [], initial.slice(1))
+      const needed = [initial[0]].concat(async, initial.slice(1))
       return needed.map(({ file }) => {
         return `<script src="${this.publicPath}${file}" defer></script>`
       }).join('')