JavaScript，Redux：数组没有价值

Question

我正在尝试为使用 Redux 操作的用户获取一些统计信息和问题，并将其传递给 React 组件。问题是，我有一个 objects 数组，curPageExercisesMarked用于页面的分页，但它不采用我分配给它的值。奇怪的是 Redux 商店中的其他字段得到了更新，但没有这个。我尝试在动作中安慰对象，但它只是打印这个：重要的是要提到我在另一个动作中做类似的事情，使用完全相同的分配，它在那里工作。我已经失去了一个小时试图弄清楚这件事，所以欢迎任何帮助。Redux 操作：export const setStatistics = (problems,problemsSolved,filter = '') => dispatch => {let payload = {subject1: 0,subject2: 0,subject3: 0,total: 0,exercisesMarked: [],curPageExercisesMarked: []};for (let i = 0; i < problems.length; i++) {  if (problems[i].S === '1' && problemsSolved.includes(problems[i]._id)) {   payload.subject1++;   payload.total++;   payload.exercisesMarked.push(problems[i]);  } else if (   problems[i].S === '2' &&   problemsSolved.includes(problems[i]._id)  ) {   payload.subject2++;   payload.total++;   payload.exercisesMarked.push(problems[i]);  } else if (   problems[i].S === '3' &&   problemsSolved.includes(problems[i]._id)  ) {   payload.subject3++;   payload.total++;   payload.exercisesMarked.push(problems[i]);  } } payload.curPageExercisesMarked = payload.exercisesMarked.slice(0, 10); dispatch({  type: SET_USER_STATISTICS,  payload });};redux 减速器：export default function(state = initialState, action) {const { type, payload } = action;switch (type) {case SET_USER_STATISTICS:  return {    ...state,    exercisesMarked: payload.exercisesMarked,    curPageExercisesMarked: payload.curPageExercisesMarked,    subject1: payload.subject1,    subject2: payload.subject2,    subject3: payload.subject3,    total: payload.total  }; case CHANGE_PAGE_MARKED:  return {    ...state,    page: payload,    curPageExercisesMarked: state.exercisesMarked.slice(      (payload - 1) * state.pages_count,      payload * state.pages_count    )  }; default:  return state; }}这是不起作用的部分： payload.curPageExercisesMarked = payload.exercisesMarked.slice(0, 10);

Answer 1

您可以先简化代码，如下所示。更新/打印console.log(JSON.stringify(payload))。我认为if(problemsSolved.includes(problems[i]._id))没有按预期工作

export const setStatistics = (

  problems,

  problemsSolved,

  filter = ""

) => dispatch => {

  let payload = {

    subject1: 0,

    subject2: 0,

    subject3: 0,

    total: 0,

    exercisesMarked: [],

    curPageExercisesMarked: []

  };

  for (let i = 0; i < problems.length; i++) {

    if(problemsSolved.includes(problems[i]._id)) {

      payload["subject"+ problems[i].S]++

      payload.total++;

      payload.exercisesMarked.push(problems[i]);

    }

  }

  payload.curPageExercisesMarked = payload.exercisesMarked.slice(0, 10);

  dispatch({

    type: SET_USER_STATISTICS,

    payload

  });

};

// 还

case SET_USER_STATISTICS:

  return {

    ...state,

    ...payload

  };