“仅在生成器主体中允许使用yield表达式” Array.prototype.map（）

Question

曾被要求重构。该代码正在运行，但不确定最终会破坏什么：

export function* fetchWidgetDataIfRequired(action) {
  yield call(taggedDelay, 102);
  const { dashboardId, dashboardType } = action.payload;

  const dashboard = yield select(makeSelectDashboard({ dashboardId, dashboardType }));
  const widgetData = yield select(makeSelectWidgets());

  const dashboardWidgets = dashboard.getIn(['config', 'widgets']);
  // get all widgets that have userWidgetId but no widgetLayoutData

  // NOTE: if you do not do valueSeq(), it will still work but it will throw a warning about
  // > [...effects] has been deprecated in favor of all([...effects]), please update your code
  const fetchWidgetLayoutDataActions = dashboardWidgets.filter((widget) => {
    '';

    const userWidgetId = widget.get('userWidgetId');

    return userWidgetId != null
      && widgetData.getIn([userWidgetId, 'widgetLayoutData']) == null;
  }).map((widget) => yield spawn(fetchWidgetLayoutData, { dashboardType, dashboardId, widget })).valueSeq().toArray();

  // console.error('fetchdata', {
  //   fetchWidgetLayoutDataActions,
  // });
  yield all(fetchWidgetLayoutDataActions);

  // get all widgets that have userWidgetId but no widgetData
  const fetchWidgetDataActions = dashboardWidgets.filter((widget) => {
    const userWidgetId = widget.get('userWidgetId');

    return userWidgetId != null
      && widgetData.getIn([userWidgetId, 'widgetData']) == null;
  }).map((widget) => {
    const userWidgetId = widget.get('userWidgetId');
    const delay = widget.get('y', 0) * 250 + 6;
    // const delay = 100;

    return spawn(fetchWidgetData, { userWidgetId, delay });
  }).valueSeq().toArray();
  yield all(fetchWidgetDataActions);
}

我被抛出此错误：

A 'yield' expression is only allowed in a generator body.ts(1163)

我很想知道如何更好地对此代码进行编码，以避免出现此错误。

Answer 1

关注功能：

.map((widget) => { // NOT A GENERATOR 
    const userWidgetId = widget.get('userWidgetId');
    const delay = widget.get('y', 0) * 250 + 6;    
    return yield spawn(fetchWidgetData, { userWidgetId, delay }); // TRIED TO USE YIELD
  })

错误是因为函数不是生成器，但是您尝试使用yield。

修复

代码是错误，因此TypeScript抱怨。我们只能在没有完整上下文的情况下推测正确的代码，但很可能以下是正确的：

.map((widget) => { 
    const userWidgetId = widget.get('userWidgetId');
    const delay = widget.get('y', 0) * 250 + 6;    
    return spawn(fetchWidgetData, { userWidgetId, delay }); // NO YIELD
  })