javascript - React JS从列表中删除特定项目

Question

我已经成功创建了一个 friend 列表，并且 addFriends 功能正常工作，即每次按下按钮时都会添加一个名为“新 friend ”的新人。

removeFriend 功能也可以使用，但如果我添加几个 friend 然后按“删除 friend ”，它会删除该键后的所有项目，而不仅仅是该键本身。我希望下面的代码只删除键 2 (George Brown)，而不是它后面的所有记录。

friendsActions.js

import * as f from '../constants'

export const addFriend = ({ firstname, lastname }) => ({
  type: f.ADD_FRIEND,
  frienditem: {
    firstname,
    lastname,
  },  
})

export const removeFriend = ({ key }) => ({
   type: f.REMOVE_FRIEND,
  key,
})

friendsReducer.js

import * as f from '../constants'

const initialState = [
  { firstname: 'John', lastname: 'Smith' },
  { firstname: 'James', lastname: 'Johnson' },
  { firstname: 'George', lastname: 'Brown' },
 ]

const friendsReducer = (state = initialState, action) => {
  switch (action.type) {
    case f.ADD_FRIEND:
      return [...state, action.frienditem] 
    case f.REMOVE_FRIEND:
      console.log('removing friend with key ' + action.key)
      return [...state.slice(0, action.key), ...state.slice(action.key + 1)]
    default:
       return state
  }
 }

export default friendsReducer

index.js(常量)

export const ADD_FRIEND = 'ADD_FRIEND'
export const REMOVE_FRIEND = 'REMOVE_FRIEND'

friendsContainer.js

import React from 'react'
import Page from '../components/Page'

import FriendList from '../containers/FriendList'

import { css } from 'glamor'

const FriendContainer = props => (
  <Page title="Friends List" colour="blue">
    <FriendList {...props} />
  </Page>
)

export default FriendContainer

friendsList.js

import React from 'react'
import { css } from 'glamor'

const Friend = ({ firstname, lastname }) => (
  <div>
    <ul>
      <li>
        {firstname} {lastname}
      </li>
    </ul>
  </div>
)

const FriendList = ({ friends, addFriend, removeFriend }) => (
  <div>
    <div>
      {friends.map((frn, i) => (
        <Friend key={++i} firstname={frn.firstname} lastname={frn.lastname} />
      ))}
    </div>
    <button onClick={() => addFriend({ firstname: 'New', lastname: 'Friend' })}>
      Add Friend
    </button>
    <button onClick={() => removeFriend({ key: '2' })}>Remove Friend</button>
  </div>
)

export default FriendList

Answer 1

您正在传递一个字符串作为操作的键:

{
  key: '3'
}

然后在代码中添加 1，在本例中为“31”。

将 state.slice(action.key + 1) 更改为 state.slice(parseInt(action.key, 10) + 1) 或将您的 key 更改为从一开始的数字。