save(minify = false) {
    const _this = this
    const data = this.data
    const stage = this.d.stage
    const doSave = {
      xml: () => _this.xmlSave(stage),
      json: minify => window.JSON.stringify(_this.prepData(stage), null, minify && '  '),
    }

    // save action for current `dataType`
    data.formData = doSave[this.config.opts.dataType](minify)

    // trigger formSaved event
    stage.dispatchEvent(new Event('formSaved', { bubbles: true, cancelable: false} ))
    return data.formData
  }
Saves and returns formData
@param {boolean} [minify=false] whether to return formatted or minified data
@return {string} formData FormData formatted in either XML or JSON depending on the current config.opts.dataType value