react+redux 初始状态的值已经赋值，但是还是报了未定义初始值的错。

Question

Warning: Failed prop type: The prop counters is marked as required in Counter, but its value is undefined.

in Counter (created by Connect(Counter))
in Connect(Counter) (at index.js:12)
in Provider (at index.js:11)

Answer 1

这是PropTypes的校验不通过的警告，看它的字面意思，也就是翻译过来就是说：
你在组件Counter 里设置了counters这个属性是isRequired的，但你忘了传这个props了，也就是值为undefined，所以校验不通过。