javascript - 如何使用 redux 为处于某种状态的数组提供唯一 ID

Question

所以每次调用我的reduce时，它都应该更新状态。这是有效的，它将新信息推送到新的数组位置。

但现在我想为每个新添加的数组位置添加一个唯一的 ID。问题是它将初始状态从 0 更改为 1，但只更改一次。我希望它增加到 2,3,4,5,....

import {GET_LOCATION} from '../actions/getLocation'
const initialState = {
    isLoaded: false,
    userLocation: [],
    error: null,
    time: null, 
    incident: null,
    Id: 0
}
function addNewLocation(state = initialState, action){
    switch(action.type){
        case GET_LOCATION:
            return {
                ...state,
                isLoaded: true,
                userLocation:[...state.userLocation, {
                    latitude: action.payload.position.coords.latitude,
                    longitude: action.payload.position.coords.longitude,
                    city: action.payload.area.city,
                    country: action.payload.area.country,
                    time: action.payload.time, 
                    incident: action.payload.incident,
                    story: 'storytime',
                    userId: state.Id +1
                }],
                }
        default:
            return state;
            }
}
export default addNewLocation

Answer 1

    import {GET_LOCATION} from '../actions/getLocation'
const initialState = {
    isLoaded: false,
    userLocation: [],
    error: null,
    time: null, 
    incident: null,
    Id: 0
}
function addNewLocation(state = initialState, action){
    switch(action.type){
        const newId = state.Id + 1; // increment ID
        case GET_LOCATION:
            return {
                ...state,
                Id: newId, // update in state
                isLoaded: true,
                userLocation:[...state.userLocation, {
                    latitude: action.payload.position.coords.latitude,
                    longitude: action.payload.position.coords.longitude,
                    city: action.payload.area.city,
                    country: action.payload.area.country,
                    time: action.payload.time, 
                    incident: action.payload.incident,
                    story: 'storytime',
                    userId: newId, // set to the userId
                }],
                }
        default:
            return state;
            }
}
export default addNewLocation