Rendering React Lists Introduction

Introduction

Welcome to the React documentation! This lab will give you an introduction to rendering lists.

Rendering Lists

The React project have already been provided in the VM. In general, you only need to add code to App.js.

Please use the following command to install the dependencies:

npm i

You will rely on JavaScript features like for loop and the array map() function to render lists of components.

For example, let’s say you have an array of products:

const products = [
  { title: "Cabbage", id: 1 },
  { title: "Garlic", id: 2 },
  { title: "Apple", id: 3 }
];

Inside your component, use the map() function to transform an array of products into an array of <li> items:

const listItems = products.map((product) => (
  <li key={product.id}>{product.title}</li>
));

return <ul>{listItems}</ul>;

Notice how <li> has a key attribute. For each item in a list, you should pass a string or a number that uniquely identifies that item among its siblings. Usually, a key should be coming from your data, such as a database ID. React uses your keys to know what happened if you later insert, delete, or reorder the items.

// App.js
const products = [
  { title: "Cabbage", isFruit: false, id: 1 },
  { title: "Garlic", isFruit: false, id: 2 },
  { title: "Apple", isFruit: true, id: 3 }
];

export default function ShoppingList() {
  const listItems = products.map((product) => (
    <li
      key={product.id}
      style={{
        color: product.isFruit ? "magenta" : "darkgreen"
      }}
    >
      {product.title}
    </li>
  ));

  return <ul>{listItems}</ul>;
}

To run the project, use the following command. Then, you can refresh the Web 8080 Tab to preview the web page.

npm start

Summary

Congratulations! You have completed the Rendering Lists lab. You can practice more labs in LabEx to improve your skills.