Javascript 如何将本地存储添加到React.js应用程序？

我有一个应用程序待办事项列表，其中包含存储不同项目的注释，如列表项、注释、注释数等

你能帮我将localStorage添加到我的应用程序中，这样所有项目都可以保存到localStorage吗

我读过一篇文章说我们需要设置两个变量的路径：key和object。如何通过所有项目传递整个状态

代码如下：

App.js

import React, { Component } from 'react';
import './App.css';
import ListInput from './components/listInput'
import ListItem from './components/listItem'
import SideBar from './components/sideBar'
import CommentsSection from './components/commentsSection'

class App extends Component {
  constructor(props){
    super(props);

    this.state = {
      items: [
        {
          id: 1, 
          title: 'First item',
          commentsCount: 0,
          comments: [],
          displayComment: false
        },
        {
          id: 2, 
          title: 'Second item',
          commentsCount: 0,
          comments: [],
          displayComment: false
        },
        {
          id: 3, 
          title: 'Third item',
          commentsCount: 0,
          comments: [],
          displayComment: false
        },
      ],
      activeItem: {},
      isHidden: true
    }
  }
  // Add new item to the list
  addItem = inputText => {
    let itemsCopy = this.state.items.slice();
    itemsCopy.push({id: this.state.items.length + 1, title: inputText, commentsCount: 0, comments: [], displayComment: false});

    this.setState({
      items: itemsCopy,
    })
  }
  // Remove the item from the list: check if the clicked button id is match 
  removeItem = id =>
    this.setState({
      items: this.state.items.filter((item, index) => item.id !== id)
    })

  addComment = (inputComment) => {
    // find item with id passed and select its comments array
     const commentCopy = this.state.items.map(item => {
       if (item.id === this.state.activeItem.id) {
         return {
           ...item, 
           commentsCount: item.comments.length + 1,
           comments: item.comments.concat({id: item.comments.length + 1, text: inputComment})
          } 
       }
         return item
      });
      this.setState({
       items: commentCopy
     })
   }

  getActiveItem = () => this.state.items.find(item => item.id === this.state.activeItem.id)

  render() {
    console.log(this.state.items.isHidden)
    return (
      <div className='App'>
        <SideBar />
        <div className='flex-container'>
          <div className='list-wrapper'>
            <h1>Items</h1>
            <ListInput inputText='' addItem={this.addItem}/>
            <ul>
              {
                this.state.items.map((item) => 
                (<ListItem 
                    item={item} 
                    key={item.id} 
                    id={item.id} 
                    removeItem={this.removeItem} 
                    setActiveComment={() => this.setState({ activeItem: item })} 
                    toggleHidden={() => this.setState({ isHidden: false })}
                  />
                ))
              }
            </ul>
          </div>
          <div>
            {!this.state.isHidden && <CommentsSection 
              addComment={this.addComment} 
              activeItem={this.getActiveItem()}
            />}
          </div>  
        </div>  
      </div>
    );
  }
}
export default App;

import React from 'react';
import CommentInput from './commentInput'
import CommentsItem from './commentsItem'
import './commentsSection.css';

export default class CommentsSection extends React.Component {
    constructor(props){
        super(props);
        this.state = {value: ''};
    }

    handleChange = event => this.setState({value: event.target.value})

    handleEnter = event => {
        if (event.charCode === 13 && event.ctrlKey) {
            console.log(this.state, this.props)
            this.addComment(this.state.value)
        } 
    }    

    addComment = comment => {
        console.log(this.props.activeComment)
         // Ensure the comment text isn't empty
        if (comment.length > 0) {
          this.props.addComment(comment);
          this.setState({value: ''});
        }   
    }

    render() {
        return (
            <div className='component-section'>
                <h1>{this.props.activeItem && this.props.activeItem.title}</h1>
                <ul>
                { this.props.activeItem &&
                    this.props.activeItem.comments.map((comment) => <p key={comment.id}>{comment.text}</p>)
                }
                </ul>
                {/*<CommentsItem />*/}
                {/*<CommentInput addComment={this.addComment}/>*/}
                <div className='comment-input'>
                    <input type='text' value={this.state.value} onChange={this.handleChange} onKeyPress={this.handleEnter}/>
                </div>
            </div>
        )
    }
}

import React from 'react';
import './listInput.css'

export default class ListInput extends React.Component {
    constructor(props){
        super(props);
        this.state = {value: this.props.inputText};

        this.handleChange = this.handleChange.bind(this);
        this.addItem = this.addItem.bind(this);
    }

    handleChange = event => this.setState({value: event.target.value})

    addItem(item) {
        // Ensure the todo text isn't empty
        if (item.length > 0) {
          this.props.addItem(item);
          this.setState({value: ''});
        }   
    }

    render() {
      return (
        <div className='list-input'>
            <input type='text' value={this.state.value} onChange={this.handleChange} placeholder={'Type name here...'}/>
            <button className='btn btn-primary' onClick={() => this.addItem(this.state.value)}>Add new</button>
        </div>
      )
    }
  }

import React，{Component}来自'React'；
导入“/App.css”；
从“./components/ListInput”导入ListInput
从“./components/ListItem”导入ListItem
从“./components/SideBar”导入侧栏
从“./components/CommentsSection”导入CommentsSection
类应用程序扩展组件{
建造师（道具）{
超级（道具）；
此.state={
项目：[
{
id:1，
标题：“第一项”，
评论：0，
评论：[]，
displayComment:false
},
{
id:2，
标题：“第二项”，
评论：0，
评论：[]，
displayComment:false
},
{
id:3，
标题:"第三项",，
评论：0，
评论：[]，
displayComment:false
},
],
活动项：{}，
伊希登：是的
}
}
//将新项目添加到列表中
addItem=inputText=>{
让itemsCopy=this.state.items.slice（）；
push（{id:this.state.items.length+1，title:inputText，commentsCount:0，comments:[]，displayComment:false}）；
这是我的国家({
项目:项目,，
})
}
//从列表中删除项目：检查单击的按钮id是否匹配
removietem=id=>
这是我的国家({
items:this.state.items.filter（（项，索引）=>item.id！==id）
})
addComment=（inputComment）=>{
//查找传递了id的项并选择其注释数组
const commentCopy=this.state.items.map（item=>{
if（item.id==this.state.activeItem.id）{
返回{
…项目，
commentsCount:item.comments.length+1，
注释：item.comments.concat（{id:item.comments.length+1，text:inputComment}）
} 
}
退货项目
});
这是我的国家({
项目：评论副本
})
}
getActiveItem=（）=>this.state.items.find（item=>item.id===this.state.activeItem.id）
render（）{
console.log（this.state.items.ishiden）
返回(
项目

{
this.state.items.map（（item）=>
（this.setState（{activeItem:item}）}
toggleHidden={（）=>this.setState（{isHidden:false}）
/>
))
}

{！this.state.ishiden&}
);
}
}
导出默认应用程序；

commentSection.js

import React, { Component } from 'react';
import './App.css';
import ListInput from './components/listInput'
import ListItem from './components/listItem'
import SideBar from './components/sideBar'
import CommentsSection from './components/commentsSection'

class App extends Component {
  constructor(props){
    super(props);

    this.state = {
      items: [
        {
          id: 1, 
          title: 'First item',
          commentsCount: 0,
          comments: [],
          displayComment: false
        },
        {
          id: 2, 
          title: 'Second item',
          commentsCount: 0,
          comments: [],
          displayComment: false
        },
        {
          id: 3, 
          title: 'Third item',
          commentsCount: 0,
          comments: [],
          displayComment: false
        },
      ],
      activeItem: {},
      isHidden: true
    }
  }
  // Add new item to the list
  addItem = inputText => {
    let itemsCopy = this.state.items.slice();
    itemsCopy.push({id: this.state.items.length + 1, title: inputText, commentsCount: 0, comments: [], displayComment: false});

    this.setState({
      items: itemsCopy,
    })
  }
  // Remove the item from the list: check if the clicked button id is match 
  removeItem = id =>
    this.setState({
      items: this.state.items.filter((item, index) => item.id !== id)
    })

  addComment = (inputComment) => {
    // find item with id passed and select its comments array
     const commentCopy = this.state.items.map(item => {
       if (item.id === this.state.activeItem.id) {
         return {
           ...item, 
           commentsCount: item.comments.length + 1,
           comments: item.comments.concat({id: item.comments.length + 1, text: inputComment})
          } 
       }
         return item
      });
      this.setState({
       items: commentCopy
     })
   }

  getActiveItem = () => this.state.items.find(item => item.id === this.state.activeItem.id)

  render() {
    console.log(this.state.items.isHidden)
    return (
      <div className='App'>
        <SideBar />
        <div className='flex-container'>
          <div className='list-wrapper'>
            <h1>Items</h1>
            <ListInput inputText='' addItem={this.addItem}/>
            <ul>
              {
                this.state.items.map((item) => 
                (<ListItem 
                    item={item} 
                    key={item.id} 
                    id={item.id} 
                    removeItem={this.removeItem} 
                    setActiveComment={() => this.setState({ activeItem: item })} 
                    toggleHidden={() => this.setState({ isHidden: false })}
                  />
                ))
              }
            </ul>
          </div>
          <div>
            {!this.state.isHidden && <CommentsSection 
              addComment={this.addComment} 
              activeItem={this.getActiveItem()}
            />}
          </div>  
        </div>  
      </div>
    );
  }
}
export default App;

import React from 'react';
import CommentInput from './commentInput'
import CommentsItem from './commentsItem'
import './commentsSection.css';

export default class CommentsSection extends React.Component {
    constructor(props){
        super(props);
        this.state = {value: ''};
    }

    handleChange = event => this.setState({value: event.target.value})

    handleEnter = event => {
        if (event.charCode === 13 && event.ctrlKey) {
            console.log(this.state, this.props)
            this.addComment(this.state.value)
        } 
    }    

    addComment = comment => {
        console.log(this.props.activeComment)
         // Ensure the comment text isn't empty
        if (comment.length > 0) {
          this.props.addComment(comment);
          this.setState({value: ''});
        }   
    }

    render() {
        return (
            <div className='component-section'>
                <h1>{this.props.activeItem && this.props.activeItem.title}</h1>
                <ul>
                { this.props.activeItem &&
                    this.props.activeItem.comments.map((comment) => <p key={comment.id}>{comment.text}</p>)
                }
                </ul>
                {/*<CommentsItem />*/}
                {/*<CommentInput addComment={this.addComment}/>*/}
                <div className='comment-input'>
                    <input type='text' value={this.state.value} onChange={this.handleChange} onKeyPress={this.handleEnter}/>
                </div>
            </div>
        )
    }
}

import React from 'react';
import './listInput.css'

export default class ListInput extends React.Component {
    constructor(props){
        super(props);
        this.state = {value: this.props.inputText};

        this.handleChange = this.handleChange.bind(this);
        this.addItem = this.addItem.bind(this);
    }

    handleChange = event => this.setState({value: event.target.value})

    addItem(item) {
        // Ensure the todo text isn't empty
        if (item.length > 0) {
          this.props.addItem(item);
          this.setState({value: ''});
        }   
    }

    render() {
      return (
        <div className='list-input'>
            <input type='text' value={this.state.value} onChange={this.handleChange} placeholder={'Type name here...'}/>
            <button className='btn btn-primary' onClick={() => this.addItem(this.state.value)}>Add new</button>
        </div>
      )
    }
  }

从“React”导入React；
从“/CommentInput”导入CommentInput
从“/CommentsItem”导入CommentsItem
导入“/commentsSection.css”；
导出默认类CommentsSection扩展React.Component{
建造师（道具）{
超级（道具）；
this.state={value:''}；
}
handleChange=event=>this.setState（{value:event.target.value}）
HandleCenter=事件=>{
if（event.charCode==13&&event.ctrlKey）{
console.log（this.state、this.props）
this.addComment（this.state.value）
} 
}    
addComment=comment=>{
log（this.props.activeComment）
//确保注释文本不是空的
如果（comment.length>0）{
this.props.addComment（comment）；
this.setState（{value:'}）；
}   
}
render（）{
返回(
{this.props.activeItem&&this.props.activeItem.title}

{this.props.activeItem&&
this.props.activeItem.comments.map（（comment）=>
{comment.text}
）
}

{/**/}
{/**/}
)
}
}

listInput.js

import React, { Component } from 'react';
import './App.css';
import ListInput from './components/listInput'
import ListItem from './components/listItem'
import SideBar from './components/sideBar'
import CommentsSection from './components/commentsSection'

class App extends Component {
  constructor(props){
    super(props);

    this.state = {
      items: [
        {
          id: 1, 
          title: 'First item',
          commentsCount: 0,
          comments: [],
          displayComment: false
        },
        {
          id: 2, 
          title: 'Second item',
          commentsCount: 0,
          comments: [],
          displayComment: false
        },
        {
          id: 3, 
          title: 'Third item',
          commentsCount: 0,
          comments: [],
          displayComment: false
        },
      ],
      activeItem: {},
      isHidden: true
    }
  }
  // Add new item to the list
  addItem = inputText => {
    let itemsCopy = this.state.items.slice();
    itemsCopy.push({id: this.state.items.length + 1, title: inputText, commentsCount: 0, comments: [], displayComment: false});

    this.setState({
      items: itemsCopy,
    })
  }
  // Remove the item from the list: check if the clicked button id is match 
  removeItem = id =>
    this.setState({
      items: this.state.items.filter((item, index) => item.id !== id)
    })

  addComment = (inputComment) => {
    // find item with id passed and select its comments array
     const commentCopy = this.state.items.map(item => {
       if (item.id === this.state.activeItem.id) {
         return {
           ...item, 
           commentsCount: item.comments.length + 1,
           comments: item.comments.concat({id: item.comments.length + 1, text: inputComment})
          } 
       }
         return item
      });
      this.setState({
       items: commentCopy
     })
   }

  getActiveItem = () => this.state.items.find(item => item.id === this.state.activeItem.id)

  render() {
    console.log(this.state.items.isHidden)
    return (
      <div className='App'>
        <SideBar />
        <div className='flex-container'>
          <div className='list-wrapper'>
            <h1>Items</h1>
            <ListInput inputText='' addItem={this.addItem}/>
            <ul>
              {
                this.state.items.map((item) => 
                (<ListItem 
                    item={item} 
                    key={item.id} 
                    id={item.id} 
                    removeItem={this.removeItem} 
                    setActiveComment={() => this.setState({ activeItem: item })} 
                    toggleHidden={() => this.setState({ isHidden: false })}
                  />
                ))
              }
            </ul>
          </div>
          <div>
            {!this.state.isHidden && <CommentsSection 
              addComment={this.addComment} 
              activeItem={this.getActiveItem()}
            />}
          </div>  
        </div>  
      </div>
    );
  }
}
export default App;

import React from 'react';
import CommentInput from './commentInput'
import CommentsItem from './commentsItem'
import './commentsSection.css';

export default class CommentsSection extends React.Component {
    constructor(props){
        super(props);
        this.state = {value: ''};
    }

    handleChange = event => this.setState({value: event.target.value})

    handleEnter = event => {
        if (event.charCode === 13 && event.ctrlKey) {
            console.log(this.state, this.props)
            this.addComment(this.state.value)
        } 
    }    

    addComment = comment => {
        console.log(this.props.activeComment)
         // Ensure the comment text isn't empty
        if (comment.length > 0) {
          this.props.addComment(comment);
          this.setState({value: ''});
        }   
    }

    render() {
        return (
            <div className='component-section'>
                <h1>{this.props.activeItem && this.props.activeItem.title}</h1>
                <ul>
                { this.props.activeItem &&
                    this.props.activeItem.comments.map((comment) => <p key={comment.id}>{comment.text}</p>)
                }
                </ul>
                {/*<CommentsItem />*/}
                {/*<CommentInput addComment={this.addComment}/>*/}
                <div className='comment-input'>
                    <input type='text' value={this.state.value} onChange={this.handleChange} onKeyPress={this.handleEnter}/>
                </div>
            </div>
        )
    }
}

import React from 'react';
import './listInput.css'

export default class ListInput extends React.Component {
    constructor(props){
        super(props);
        this.state = {value: this.props.inputText};

        this.handleChange = this.handleChange.bind(this);
        this.addItem = this.addItem.bind(this);
    }

    handleChange = event => this.setState({value: event.target.value})

    addItem(item) {
        // Ensure the todo text isn't empty
        if (item.length > 0) {
          this.props.addItem(item);
          this.setState({value: ''});
        }   
    }

    render() {
      return (
        <div className='list-input'>
            <input type='text' value={this.state.value} onChange={this.handleChange} placeholder={'Type name here...'}/>
            <button className='btn btn-primary' onClick={() => this.addItem(this.state.value)}>Add new</button>
        </div>
      )
    }
  }

从“React”导入React；
导入“./listInput.css”
导出默认类ListInput扩展React.Component{
建造师（道具）{
超级（道具）；
this.state={value:this.props.inputText}；
this.handleChange=this.handleChange.bind（this）；
this.addItem=this.addItem.bind（this）；
}
handleChange=event=>this.setState（{value:event.target.value}）
附加项（项目）{
//确保待办事项文本不是空的
如果（item.length>0）{
本.道具.附件（项目）；
this.setState（{value:'}）；
}   
}
render（）{
返回(
this.addItem（this.state.value）}>addnew
)
}
}

React使操作变得非常简单

// setter
localStorage.setItem('myData', data);

// getter
localStorage.getItem('myData');

---

您可以通过浏览器自动访问

localStorage

对象。请记住，

.setItem

没有返回值，所以只需同步使用它。

React使其非常简单

// setter
localStorage.setItem('myData', data);

// getter
localStorage.getItem('myData');

您可以通过浏览器自动访问

localStorage

对象。请记住，

.setItem

没有返回值，所以只需同步使用它。

一个简单的解释： localStorage有两种重要的方法：

• localStorage.setItem（*名称*，*字符串值*）

  • 参数

    name

    只是希望存储在存储器中以方便引用数据的键
  • 参数

    字符串值

    只是希望存储在

    键/name

    下的值。重要的是