使用 Redux 将对象添加到数组时,由于某种原因,添加第一条记录不起作用。
我会收到以下错误:
TypeError: Invalid attempt to spread non-iterable instance. in order to be iterable, non-array objects must have a [Symbolic.iterator]()method.
使用此代码:
case POST_COMMENTS_ADD:
return {
...state,
comments: [...state.comments, action.newItem[0]],
lastKey: null,
noData: null,
};
我想了解为什么这种方法在我认为应该有效的时候却不起作用。
这是我管理它添加的方式(第一条记录没有错误 - 所有后续添加都可以在初始代码中正常工作)
case POST_COMMENTS_ADD:
return {
...state,
comments: !state.comments ? [action.newItem[0]] : [...state.comments, action.newItem[0]],
lastKey: null,
noData: null,
};
修复有效,但我想看看第一种方法哪里出错了。
这是我的整个减速器:
import {
POST_COMMENTS_FETCH_SUCCESS,
POST_COMMENTS_NO_DATA,
UNMOUNT_POST_COMMENTS,
POST_COMMENTS_ADD,
} from '../actions/types';
const INITIAL_STATE = {
comments: [],
};
export default (state = INITIAL_STATE, action) => {
switch (action.type) {
case POST_COMMENTS_FETCH_SUCCESS:
return {comments: action.payload, lastKey: action.key, noData: null};
case POST_COMMENTS_NO_DATA:
return {comments: null, lastKey: null, noData: true};
case POST_COMMENTS_ADD:
return {
...state,
comments: !state.comments ? [action.newItem[0]] : [action.newItem[0], ...state.comments],
lastKey: null,
noData: null,
};
case UNMOUNT_POST_COMMENTS:
return {comments: null, noData: null};
default:
return state;
}
};