如何在对象数组中添加一个对象?ReactJS? [英] How to add an object in an array of objects? ReactJS?

问题描述

我的项目是一个对象数组，其中我只获取名称并在 3 合 3 的屏幕上呈现，使用下一个和上一个按钮更改名称，并且可以过滤字母.

我想添加一个新值，在输入中输入并单击 add 按钮.

我的代码按钮:

addItem = () =>{const inValue = {编号:0，名称:this.state.input}this.setState({过滤:this.state.filtered.concat(inValue),当前页面:0})}

我希望将值插入到 filtered 数组中.

我的代码全部:

import React, { Component } from 'react';类 App 扩展组件 {构造函数(){极好的();const peoples =[{id:0, name:"Jean"},{id:1, name:"Jaha"},{id:2, name:"Rido"},{id:3, name:"Ja"},{id:4, name:"Letia"},{id:5, name:"Di"},{id:6, name:"Dane"},{id:7, name:"Tamy"},{id:8, name:"Tass"},{id:9, name:"Ts"},{id:10, name:"Abu"},{id:11, name:"Ab"}];this.state = {每页元素:3，当前页:0,人们，输入: ""，过滤:人民，睾丸:'',};}getValueInput = (evt) =>{const inputValue = evt.target.value;this.setState({ input: inputValue });this.filterNames(inputValue);}filterNames = (inputValue)=>{const { people} = this.state;this.setState({过滤:peoples.filter(item =>item.name.includes(inputValue)),当前页:0});const Oi = this.state.filtered.map(item=>item.name);if(Oi.length<=0){alert('Você está adicionando um nome')}控制台日志(Oi)}elementOnScreen = () =>{const {elementsPerPage，currentPage，filtered} = this.state;返回过滤.map((item) => 
 {item.name}  this.remove(item.name)}> 删除 <;/button> 
).slice(currentPage*elementsPerPage, currentPage*elementsPerPage + elementsPerPage);if(this.state.filtered.length < 1){this.setState({currentPage: this.state.currentPage - 1})}}移除 = (id) =>{console.log(this.state.filtered.length)if(this.state.filtered.length <0){this.setState({currentPange: this.state.currenPage - 1})}this.setState({filtered: this.state.filtered.filter(item => item.name !== id) })}nextPage = () =>{console.log(this.state.filtered)const {elementsPerPage，currentPage，filtered} = this.state;if ((currentPage+1) * elementsPerPage {const { currentPage } = this.state;if(currentPage - 1 >= 0){this.setState({ currentPage: this.state.currentPage - 1 });}}addItem = () =>{const inValue = {id:0 ,name: this.state.input}this.setState({filtered: this.state.filtered.concat(inValue), currentPage: 0})}使成为() {返回 (<div><button onClick={this.addItem}>添加</button><input type="text" onChange={ this.getValueInput }></input><button onClick={this.previousPage}>上一个 </button><button onClick={this.nextPage}>下一个</button><h3>当前页面:{this.state.currentPage}</h3><ul>名称:{this.elementsOnScreen()}</ul>

);}}导出默认应用；

解决方案

您将拥有包含在状态中的对象数组，然后使用 setState

this.state = {每页元素:3，当前页:0,人们，输入: ""，过滤:人民，睾丸:'',人们: [{id:0, name:"Jean"},{id:1, name:"Jaha"},{id:2, name:"Rido"},{id:3, name:"Ja"},{id:4, name:"Letia"},{id:5, name:"Di"},{id:6, name:"Dane"},{id:7, name:"Tamy"},{id:8, name:"Tass"},{id:9, name:"Ts"},{id:10, name:"Abu"},{id:11, name:"Ab"}];};

要更新 peoples 数组，您首先需要创建 peoples 数组的副本，修改副本，然后使用 setState 进行更新.

let { peoples } = this.state;peoples.push({ id:12, name:"Jean"})this.setState({peoples: peoples})

My Project is, an array of objects where i get only the names and render on screen of form 3 in 3, with button next and previous change the names, and can to filter for letters.

I would want add a new value, typped on input and clicked in the button add.

My code button:

addItem = () => {
  const inValue = {
    id: 0,
    name: this.state.input
  }
  this.setState({
    filtered: this.state.filtered.concat(inValue),
    currentPage: 0
  })
}

I would want the value inserted in the filtered array.

My code all:

import React, { Component } from 'react';

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

    const peoples =[{id:0, name:"Jean"}, 
      {id:1, name:"Jaha"}, 
      {id:2, name:"Rido"}, 
      {id:3, name:"Ja"}, 
      {id:4, name:"Letia"}, 
      {id:5, name:"Di"}, 
      {id:6, name:"Dane"}, 
      {id:7, name:"Tamy"}, 
      {id:8, name:"Tass"},
      {id:9, name:"Ts"}, 
      {id:10, name:"Abu"}, 
      {id:11, name:"Ab"}];
    
    this.state = {
      elementsPerPage:3,
      currentPage:0,
      peoples,
      input: "",
      filtered: peoples,
      teste: '',
    };


  } 
  
getValueInput = (evt) => {
  const inputValue = evt.target.value;
  this.setState({ input: inputValue });
  this.filterNames(inputValue);
}

filterNames = (inputValue)=> {
  const { peoples } = this.state;
  this.setState({
    filtered: peoples.filter(item => 
       item.name.includes(inputValue)),
    currentPage:0
  });
  const Oi = this.state.filtered.map(item=>item.name);
if(Oi.length<=0){
  alert('Você está adicionando um nome')
}
    console.log(Oi)
  }

  
  elementsOnScreen = () => {
    const {elementsPerPage, currentPage, filtered} = this.state;
    return filtered
      .map((item) => <li key={item.id}> {item.name} <button onClick={() => this.remove(item.name)}> Delete </button> </li>)
      .slice(currentPage*elementsPerPage, currentPage*elementsPerPage + elementsPerPage);
    
    if(this.state.filtered.length < 1){
      this.setState({currentPage: this.state.currentPage - 1})
    }
   
  }

  remove = (id) => {
  console.log(this.state.filtered.length)
    if(this.state.filtered.length < 0){
       this.setState({currentPange: this.state.currenPage - 1})
    }
  this.setState({filtered: this.state.filtered.filter(item => item.name !== id) })
}
  
 nextPage = () => {
         console.log(this.state.filtered)

    const {elementsPerPage, currentPage, filtered} = this.state;
    
    if ((currentPage+1) * elementsPerPage < filtered.length){
      this.setState({ currentPage: this.state.currentPage + 1 });
    }
  }
  
    previousPage = () => {
      const { currentPage } = this.state;
      if(currentPage - 1 >= 0){
         this.setState({ currentPage: this.state.currentPage - 1 });
      }
  }
    addItem = () =>{
        const inValue = {id:0 ,name: this.state.input}
        this.setState({filtered: this.state.filtered.concat(inValue), currentPage: 0})
      }
    

  render() {
    return (
      <div>
        <button onClick={this.addItem}> Add </button>
        <input type="text" onChange={ this.getValueInput }></input>
        <button onClick={this.previousPage}> Previous </button>
        <button onClick={this.nextPage}> Next </button>
        <h3>Current Page: {this.state.currentPage}</h3>
        <ul>Names: {this.elementsOnScreen()}</ul>
      </div>
    );
  }
}

export default App;

解决方案

You would have the array of objects contained within your state, then use setState

this.state = {
      elementsPerPage:3,
      currentPage:0,
      peoples,
      input: "",
      filtered: peoples,
      teste: '',
      peoples: [
  {id:0, name:"Jean"}, 
  {id:1, name:"Jaha"}, 
  {id:2, name:"Rido"}, 
  {id:3, name:"Ja"}, 
  {id:4, name:"Letia"}, 
  {id:5, name:"Di"}, 
  {id:6, name:"Dane"}, 
  {id:7, name:"Tamy"}, 
  {id:8, name:"Tass"},
  {id:9, name:"Ts"}, 
  {id:10, name:"Abu"}, 
  {id:11, name:"Ab"}];
    };

To update the peoples array, you would first need to create a copy of the peoples array, modify the copy, then use setState to update.

let { peoples } = this.state;
peoples.push({ id:12, name:"Jean"}) 
this.setState({peoples: peoples})

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