Expressions in propTypes not parsed correctly

Originally reported in https://github.com/sapegin/react-styleguidist/issues/13#issuecomment-146868948.

I use an expression in React.PropTypes.oneOf(...). This is the output from react-docgen:

{
  "description": "",
  "props": {
    "issue": {
      "type": {
        "name": "object"
      },
      "required": false,
      "description": ""
    },
    "width": {
      "type": {
        "name": "enum",
        "computed": true,
        "value": "_.map(_.keys(coverWidths), _.parseInt)" <------- problem
      },
      "required": false,
      "description": ""
    },
    "style": {
      "type": {
        "name": "object"
      },
      "required": false,
      "description": ""
    }
  }
}

coverWidths is a variable defined in that file. In runtime it's generated correctly, but react-docgen can't parse it.

value in the marked line should be null, and there should be a raw property with it instead.

@fkling confirmed that this is is a bug in react-docgen.

Comienza localizando el punto de entrada del parser de propTypes que gestiona las expresiones calculadas, usando como caso de reproducción el ejemplo de React.PropTypes.oneOf de este issue. Verifica la salida generada para .map(.keys(coverWidths), _.parseInt); terminado significa que value es null y que la expresión se conserva en una propiedad raw.