React Missing class properties transform.

Missing class properties transform.

描述:

ERROR in ./app/components/MsgComponent/msgAdd.js
Module build failed: SyntaxError: Missing class properties transform.

  73 |  }
  74 |
> 75 |     handleClearContent = () => {
     |     ^
  76 |         this.setState({
  77 |             editorState:''
  78 |         })

解决: