[InputItem]type=money,defaultValue or value = some number then can't delete the default value use virtual keyboard

[DragonCat1]

• I have searched the issues of this repository and believe that this is not a duplicate.

Version

2.1.8

Environment

react 16.3.1 chrome

Reproduction link

https://github.com/ant-design/ant-design-mobile

Steps to reproduce

1.type=money
2.defaultValue or value = some number
3.delete initial value use virtual keyboard

What is expected?

can delete initial value

What is actually happening?

Uncaught TypeError: value.substring is not a function
at NumberInput._this.onKeyboardClick (CustomInput.js:136)
at CustomKeyboard._this2.onKeyboardClick (CustomKeyboard.js:117)
at onClick (CustomKeyboard.js:87)
at HTMLUnknownElement.callCallback (react-dom.development.js:100)
at Object.invokeGuardedCallbackDev (react-dom.development.js:138)
at Object.invokeGuardedCallback (react-dom.development.js:187)
at Object.invokeGuardedCallbackAndCatchFirstError (react-dom.development.js:201)
at executeDispatch (react-dom.development.js:466)
at executeDispatchesInOrder (react-dom.development.js:488)
at executeDispatchesAndRelease (react-dom.development.js:586)

[15738039217]

我用defaultValue或value =某个汉字，然后onChange监听输入的值给value，不能输入汉字，键盘一直闪

[micooz]

@15738039217 能否新开 issue 给出复现的 demo？