How to set the Dynamic Field value? Form

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

Version

3.9.2

Environment

mac os 10.13.6 (17G2307) 
chrome  69.0.3497.81（正式版本） （64 位）

Reproduction link

Steps to reproduce

1. press Add field
2. press 报错
3. press 可以添加

What is expected?

can set the value of a component based on dynamic field name

What is actually happening?

Warning: You cannot set a form field before rendering a field associated with the value.

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如何用setFieldsValue()给动态添加的文本框进行赋值?

[afc163]

Please learn ES6 seriously.

https://codesandbox.io/s/3q35povy1p

    this.props.form.setFieldsValue({
-     a: 'antd'
+     [a]: 'antd'
    });

[sundayha]

@afc163 ok! thanks!!