Deleting an item in ReactJS

Let me guess, Are you looking for something like this?

class Example extends React.Component {    constructor(){    this.state = {      data: [        {id:1, name: 'Hello'},        {id:2, name: 'World'},        {id:3, name: 'How'},        {id:4, name: 'Are'},        {id:5, name: 'You'},        {id:6, name: '?'}      ]    }  }  // shorter & readable   delete(item){    const data = this.state.data.filter(i => i.id !== item.id)    this.setState({data})  }  // or this way, it works as well  //delete(item){  //  const newState = this.state.data.slice();  //    if (newState.indexOf(item) > -1) {  //    newState.splice(newState.indexOf(item), 1);  //    this.setState({data: newState})  //  }  //}  render(){    const listItem = this.state.data.map((item)=>{        return <div key={item.id}>        <span>{item.name}</span> <button onClick={this.delete.bind(this, item)}>Delete</button>      </div>    })    return <div>        {listItem}    </div>  }}React.render(<Example />, document.getElementById('container'));

In this example pay attention how i'm binding delete method and pass there new parameter. fiddle

I hope it will help you.

Thanks

OP here. Since I know more about React four years later and this still gets views I figured I'd update this with how I'd go about it now.

SavedSearches.js

import React from 'react'import { SearchList } from './SearchList'let data = [    {index: 0, name: "a string", url: 'test.com/?search=string'},    {index: 1, name: "a name", url: 'test.com/?search=name'},    {index: 2, name: "return all", url: 'test.com/?search=all'}  ];let startingIndex = data.length;export class SavedSearches extends React.Component {    constructor(props) {        super(props);        this.state = {            name: '',            url: '',            index: startingIndex,            data: data        }        this.deleteSearch=this.deleteSearch.bind(this)    }    deleteSearch(deleteThis) {        console.log(deleteThis);        let newData = this.state.data.filter( searchItem => searchItem.index !== deleteThis.index )        this.setState({            data: newData        })    }    render() {        return (            <div className="search-container">                <SearchList data={this.state.data} onDelete={this.deleteSearch}/>            </div>        )    }}

Here I created a method called deleteSearch that takes an object as a parameter. It then runs .filter on the this.state.data array to create a new array that includes all items that don't meet the condition. The condition checks if the id of each object in the data array matches the id of the parameter. If so, then it is the one that is being deleted. The new array that is created by .filter is set to a variable called newData, and then I update the state with the newData array.

I then pass this method to the SearchList component in a prop called onDelete.

This method is also bound in the constructor using .bind() so that this will refer to the correct this when the method is passed down the component tree.

SearchList.js

import React from 'react'import { SearchItem } from './SearchItem'export class SearchList extends React.Component {    render() {      let searchItems = this.props.data.map((item, i) => {        return (          <SearchItem index={i} searchItem={item} url={item.url} onDelete={this.props.onDelete}>            {item.name}          </SearchItem>        );      });      return (        <ul>          {searchItems}        </ul>      );    }}

My deleteSearch method is just passing through the component tree here. SearchList receives the method as a props this.props.onDelete and passes it to SearchItem.

The other major key here is that the parameter in the map function is being passed as props: searchItem={item}. This will allow the entire current object to be accessed via props; and if you remember, my deleteSearch function takes an object as a parameter.

SearchItem.js

import React from 'react'export class SearchItem extends React.Component {    constructor(props) {        super(props);        this.handleDelete=this.handleDelete.bind(this)    }    handleDelete() {        this.props.onDelete(this.props.searchItem)    }    render() {      return (        <li key={this.props.index}> {/* Still getting a console error over this key */}          <a href={this.props.url} title={this.props.name}>            {this.props.children}          </a>           ({this.props.url})          <button onClick={this.handleDelete} value={this.props.index}><i className="fa fa-times"></i>          </button>        </li>      );    }  };

Now my method arrives where it will be used. I create a handler method handleDelete and inside I access the deleteSearch method with this.props.onDelete. I then pass it the object of the list item that is being clicked on with this.props.searchItem.

In order for this to work when a user clicks, I had to add an onClick event listener that calls my handler method, like this: onClick={this.handleDelete}. The final step is to bind this.handleDelete in the SearchItem constructor method.

Now, clicking on the button will remove the item from the this.state.data array. For an example of how to add an item to the array, see my repository

Are you looking for somthing like this?

Todos.js

import React from 'react'import {TodoItem} from "./TodoItem";export const Todos = (props) => {    let myStyle = {        minHeight: "70vh",        margin: "40px auto"    }    return (        <div className="container" style={myStyle}>            <h3 className="my-3">List</h3>            {props.todos.length===0? "No records to display":              props.todos.map((todo)=>{                console.log(todo.sno);                return (<TodoItem todo={todo} key={todo.sno} onDelete={props.onDelete}/>                   )            })              }         </div>    )}

TodoItem.js

import React from 'react'export const TodoItem = ({todo, onDelete}) => {    return (        <>        <div>           <h4>{todo.title}</h4>           <p>{todo.desc}</p>           <button className="btn btn-sm btn-danger" onClick={()=>{onDelete(todo)}}>Delete</button>         </div>        <hr/>         </>    )}

Please see the repository, here you can find add ,delete and list items