refactor: tweak data merge strategy (#6833)

HcySunYang · yyx990803 · commit ee0e8b5ce1d6 · 2017-10-25T06:48:12.000+02:00
* tweak: The value of this is always undefined

* parentVal and childVal must have a presence, otherwise the strats.data policy function will not be executed
diff --git a/src/core/util/options.js b/src/core/util/options.js
@@ -89,7 +89,7 @@ export function mergeDataOrFn (
         typeof parentVal === 'function' ? parentVal.call(this) : parentVal
       )
     }
-  } else if (parentVal || childVal) {
+  } else {
     return function mergedInstanceDataFn () {
       // instance merge
       const instanceData = typeof childVal === 'function'
@@ -123,7 +123,7 @@ strats.data = function (
 
       return parentVal
     }
-    return mergeDataOrFn.call(this, parentVal, childVal)
+    return mergeDataOrFn(parentVal, childVal)
   }
 
   return mergeDataOrFn(parentVal, childVal, vm)

Original file line number	Diff line number	Diff line change
`@@ -89,7 +89,7 @@ export function mergeDataOrFn (`
`89`	`89`	`typeof parentVal === 'function' ? parentVal.call(this) : parentVal`
`90`	`90`	`)`
`91`	`91`	`}`
`92`		`- } else if (parentVal \|\| childVal) {`
	`92`	`+ } else {`
`93`	`93`	`return function mergedInstanceDataFn () {`
`94`	`94`	`// instance merge`
`95`	`95`	`const instanceData = typeof childVal === 'function'`
`@@ -123,7 +123,7 @@ strats.data = function (`
`123`	`123`
`124`	`124`	`return parentVal`
`125`	`125`	`}`
`126`		`- return mergeDataOrFn.call(this, parentVal, childVal)`
	`126`	`+ return mergeDataOrFn(parentVal, childVal)`
`127`	`127`	`}`
`128`	`128`
`129`	`129`	`return mergeDataOrFn(parentVal, childVal, vm)`