Render arrays with map().
✍️ 3 exercises + code challenge in this lessonRender a list by mapping an array to JSX elements: {items.map(item => <li>{item.name}</li>)}
Each item needs a unique key prop so React can track which items changed. Use a stable id from your data, not the array index, when items can be reordered or removed.
Mastering React Lists & Keys helps you write clean and reliable React code. Follow standard conventions, test edge cases, and keep logic simple. Try running the code example below and complete the exercises to build confidence.
<div id="root"></div>
<script src="https://unpkg.com/react@18.3.1/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@18.3.1/umd/react-dom.development.js"></script>
<script src="https://unpkg.com/@babel/standalone@7.25.6/babel.min.js"></script>
<script type="text/babel">
const { useState, useEffect, useRef, useMemo, createContext, useContext } = React;
const students = [
{ id: 1, name: "Ali", marks: 81 },
{ id: 2, name: "Sara", marks: 94 },
{ id: 3, name: "Usman", marks: 62 },
];
function App() {
const sorted = [...students].sort((a, b) => b.marks - a.marks);
return (
<ol>
{sorted.map((s) => (
<li key={s.id}>
{s.name}: <strong>{s.marks}</strong> {s.marks >= 90 && "🏆"}
</li>
))}
</ol>
);
}
ReactDOM.createRoot(document.getElementById("root")).render(<App />);
</script>Check what you learned in “React Lists & Keys”.
Every list item needs a unique…
{items.map(item => <li ={item.id}>{item.name}</li>)}
Which array method is used to render lists in JSX?
Render the fruits array as <li> items inside a <ul>.
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