code: function transformModel (options, data) {
    const prop = (options.model && options.model.prop) || 'value'
    const event = (options.model && options.model.event) || 'input';
    (data.props || (data.props = {}))[prop] = data.model.value
    const on = data.on || (data.on = {})
    if (isDef(on[event])) {
      on[event] = [data.model.callback].concat(on[event])
    } else {
      on[event] = data.model.callback
    }
  }
docs: transform component v-model info (value and callback) into prop and event handler respectively.