React Tutorials
React Introduction
React Get Started
React Render HTML
React JSX
React Components
React Class
React Props
React Events
React Conditionals
React Lists
React Forms
React Router
React Memo
React CSS Styling
React Sass Styling
React ES6
React ES6
ES6 Classes
ES6 Arrow Functions
ES6 Variables
ES6 Array Methods
ES6 Destructing
ES6 Spread Operator
ES6 Modules
ES6 Ternary Operator
React Hooks
What is Hook?
useState
useContext
useRef
useReducer
useCallback
useMemo
Custom Hooks
Previous
React Lists
In React, you will provide lists by type of loop.
The JavaScript map() method for similar members is usually the preferred method.
If you need to update on the map() route, check the ES6 section.
Example
Let's render all of the cars from our garage:
function Car(props) {
return <li>I am a { props.brand }</li>;
}
function Garage() {
const cars = ['Ford', 'BMW', 'Audi'];
return (
<>
<h1>Who lives in my garage?</h1>
<ul>
{cars.map((car) => <Car brand={car} />)}
</ul>
</>
);
}
ReactDOM.render(<Garage />, document.getElementById('root'));
If you use this code in your create-react-app, it will work but you will receive a warning that there is no "key" provided for list items.
Keys
Keys allow React to track features. This way, if an item is updated or removed, only that item will be redirected instead of the whole list.
The keys must be different for each sibling. But they can be repeated worldwide.
Generally, the key should be a unique ID assigned to each item. As a last resort, you can use the array index as a key.
Example
Let's refactor our previous example to include keys:
function Car(props) {
return <li>I am a { props.brand }</li>;
}
function Garage() {
const cars = [
{id: 1, brand: 'Ford'},
{id: 2, brand: 'BMW'},
{id: 3, brand: 'Audi'}
];
return (
<>
<h1>Who lives in my garage?</h1>
<ul>
{cars.map((car) => <Car key={car.id} brand={car.brand} />)}
</ul>
</>
);
}
ReactDOM.render(<Garage />, document.getElementById('root'));