Error when trying to use .onAdd

Hi, I tried adding an ‘Add Members’ button on your demo form.

<button type="button" onClick={e => form.$('members').onAdd(e)}>
  <i className="fa fa-plus-circle" data-tip="Add Members" />
</button>

I get the following error: Uncaught Error: The selected field is not defined (firstname)

[foxhound87]

I recently implemented pathToFieldsTree method, which we can use to create an object tree starting from a string path: https://github.com/foxhound87/mobx-react-form/blob/fb0eb6a535bd6f52c5c355409ee3cc02b9a1c61e/src/FieldParser.js#L16

I think we can start from here to create the object with empty fields for each of the path struct we need to add.

[itaylorweb]

@foxhound87 This is great thanks. Works perfectly.