Why and how to set key on each component in a collection so React can keep track of each of them even if their position or data changes. 1. Splitting a list in two 2. Nested lists in one component 3. Extracting a list item component 4. List with a separator · This example shows a list of all people.

Let's create a simple list using the map() method: function MyCars() { const cars = ['Ford', 'BMW', 'Audi']; return ( <> <h1>My Cars:</h1> <ul> {cars.map((car) => <li>I am a { car }</li>)} </ul> </> ); } createRoot(document.getElementById('root')).render( <MyCars /> ); Run Example » · When you run this code in your React environment, it will work but you will receive a warning that there is no "key" provided for the list items.

<List sx={{ width: '100%', maxWidth: 360, bgcolor: 'background.paper' }}> {[1, 2, 3].map((value) => ( <ListItem key={value} disableGutters secondaryAction={ <IconButton aria-label="comment"> <CommentIcon /> </IconButton> } > <ListItemText ...

April 16, 2019 - Hence you can access the object ... from 'react'; const list = [ { id: 'a', firstname: 'Robin', lastname: 'Wieruch', year: 1988, }, { id: 'b', firstname: 'Dave', lastname: 'Davidds', year: 1990, }, ]; const ComplexList = ...

December 10, 2024 - Here's another simple example to get you started. import loadAccount from 'my-account-loader'; import React from 'react'; import ReactList from 'react-list'; class MyComponent extends React.Component { state = { accounts: [] }; componentWillMount() { loadAccounts(::this.handleAccounts); } handleAccounts(accounts) { this.setState({accounts}); } renderItem(index, key) { return <div key={key}>{this.state.accounts[index].name}</div>; } render() { return ( <div> <h1>Accounts</h1> <div style={{overflow: 'auto', maxHeight: 400}}> <ReactList itemRenderer={::this.renderItem} length={this.state.accounts.length} type='uniform' /> </div> </div> ); } }

April 9, 2026 - Lists display dynamic data like users, products, or tasks in a structured way. The map() function iterates over arrays and returns JSX for each item. A unique key prop helps React efficiently update and re-render elements.

We can refactor the previous example into a component that accepts an array of numbers and outputs a list of elements. function NumberList(props) { const numbers = props.numbers; const listItems = numbers.map((number) => <li>{number}</li> ); ...

February 27, 2025 - These reusable components are fundamental building blocks in React, as they help manage and present data in a structured and dynamic manner. Examples of list components include itemized lists, tables, grids, and more.

Use this online react-list playground to view and fork react-list example apps and templates on CodeSandbox.

November 16, 2023 - Lists are collections of elements that can be rendered using JSX syntax. JSX allows us to write HTML-like code in JavaScript and use it as React components. For example, we can create a list of numbers using an array and JSX:

class ContactRow extends React.Component { render() { return ( <tr> <td>{this.props.contact.name}</td> <td>{this.props.contact.phone}</td> <td>{this.props.contact.email}</td> </tr> ); } } class ContactTable extends React.Component { render() { var rows = []; this.props.contacts.forEach((contact) => { if (contact.name.indexOf(this.props.filterText) === -1) { return; } rows.push(<ContactRow contact={contact} />); }); return ( <table className='table'> <thead> <tr> <th>Name</th> <th>Phone</th> <th>Email</th> </tr> </thead> <tbody>{rows}</tbody> </table> ); } } class SearchBar extends React.Compon

React can look at the key and know that, yes, even though this <Item> is not strictly === to the old <Item>, it actually is the same because the keys are the same. This leads to a couple rules for keys. They must be: Unique – Every item in the list must have a unique key. So, person.firstName would be a bad choice, for example (might not be unique).

// Employee Component class Employee extends React.Component { render() { return ( <li className="employee"> <div> <b>Full Name:</b> {this.props.fullName} </div> <div> <b>Gender:</b> {this.props.gender} </div> </li> ); } } // EmployeeList Component class EmployeeList extends React.Component { constructor(props) { super(props); this.state = { employees: [ { empId: 1, fullName: "Trump", gender: "Male" }, { empId: 2, fullName: "Ivanka", gender: "Female" }, { empId: 3, fullName: "Kushner", gender: "Male" } ] }; } render() { // Array of <Employee> var listItems = this.state.employees.map(e => ( <Employee key={e.empId} fullName={e.fullName} gender={e.gender} /> )); return ( <ul className="employee-list"> {listItems} </ul> ); } } // Render ReactDOM.render(<EmployeeList />, document.getElementById("employeelist1"));

July 1, 2026 - This React demo provides a robust example of a native Drag and Drop (DnD) list.

February 28, 2025 - Today, we’ll build a simple User List component using .map() and style it for better presentation. ✅ How to use .map() to iterate over an array and display data dynamically. ✅ The importance of unique keys in React lists.

August 12, 2026 - The FlatList component requires ... the source and returns a formatted component to render. This example creates a basic FlatList of hardcoded data. Each item in the data props is rendered as a Text component....

September 17, 2024 - Imagine you're building a dashboard for an e-commerce application. The dashboard includes several lists: recent orders, top-selling products, user comments, etc. You need to render each list using a .map() function.

May 14, 2020 - We will be using React’s useState Hook, to keep this first example simple, however, you can also use React’s useReducer Hook, as you will see later. We will start with a typical list in React where we provide a stable key attribute for each rendered list item:

June 4, 2024 - It also takes the rowHeight prop, which represents the height of every item in the list, and rowCount, which represents the length of the array. rowRenderer takes a function that is responsible for rendering each row: react-virtualized comes with several other options for handling large lists.

April 7, 2024 - The key prop helps React identify which items have changed, been added, or been removed, and is necessary for efficient list rendering in React. The resulting JSX is a list of <li> elements, each containing one of the items from the items array. When the ListComponent is rendered, it will generate a list of fruits based on the data in the items array. This is a simple example, but you can apply the same technique to render more complex components within the list, allowing for flexible and dynamic UIs in React applications.