fixed #3942 (#3947)

leon lau · yyx990803 · commit 341d0a03570f · 2016-10-17T10:43:39.000+08:00
* fixed #3942 * fixed #3942
diff --git a/src/core/observer/index.js b/src/core/observer/index.js
@@ -186,6 +186,7 @@ export function defineReactive (
  */
 export function set (obj: Array<any> | Object, key: any, val: any) {
   if (Array.isArray(obj)) {
+    obj.length = Math.max(obj.length, key)
     obj.splice(key, 1, val)
     return val
   }

Original file line number	Diff line number	Diff line change
`@@ -186,6 +186,7 @@ export function defineReactive (`
`186`	`186`	`*/`
`187`	`187`	`export function set (obj: Array<any> \| Object, key: any, val: any) {`
`188`	`188`	`if (Array.isArray(obj)) {`
	`189`	`+ obj.length = Math.max(obj.length, key)`
`189`	`190`	`obj.splice(key, 1, val)`
`190`	`191`	`return val`
`191`	`192`	`}`