whole_func_string: function backTo(stateName, defaultParams, acc) {
      const params = leafStates[stateName].lastParams || defaultParams
      transitionTo(stateName, params, acc)
    }
func_code_string: function backTo(stateName, defaultParams, acc) {
      const params = leafStates[stateName].lastParams || defaultParams
      transitionTo(stateName, params, acc)
    }
func_documentation_string: /*
  Attempt to navigate to 'stateName' with its previous params or
  fallback to the defaultParams parameter if the state was never entered.