fixed #3942 (#3947)

* fixed #3942 * fixed #3942
8 years ago · 341d0a0357
1 changed files with 1 additions and 0 deletions
--- 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
  }