React DocsのQuick StartをTypeScriptで書き直してみた

Keita 1 February 2023 開発, React, TypeScript,

概要

Reactの公式ドキュメントの新しいものがbeta版ですが公開されています。( https://beta.reactjs.org/ )

こちらは関数コンポーネントを学習するのにおすすめとなっております。(2023/02/01現在英語版のみ。)

さて、
ReactとTypeScriptの学習も兼ねて、
Quick StartのThinking in React( https://beta.reactjs.org/learn/thinking-in-react )をTypeScriptに書き直してみました。

環境

WSL2(Ubuntu 20.04.5)

Node.js 16.14.0

React 18.2.0

Create React App 5.0.1

TypeScript 4.8.4

環境構築

$ npx create-react-app sample_app --template typescript

プロジェクトを実行

$ npm start

ソースコード

各コンポーネントは「components」ディレクトリにファイルを作成した
propsの型定義は各コンポーネントファイルに記述した
複数箇所で共通で使用している型定義は「types」ディレクトリにファイルを作成した

src/components/FilterableProductTable.tsx

import { useState } from 'react';

import { SearchBar } from './SearchBar';

import { ProductTable } from './ProductTable';

import type { Product } from '../types/ProductType';

type Props = {

products: Product[];

};

export const FilterableProductTable: React.FC<Props> = ({ products }) => {

const [filterText, setFilterText] = useState('');

const [inStockOnly, setInStockOnly] = useState(false);

return (

<>

<SearchBar

filterText={filterText}

inStockOnly={inStockOnly}

onFilterTextChange={setFilterText}

onInStockOnlyChange={setInStockOnly}

/>

<ProductTable products={products} filterText={filterText} inStockOnly={inStockOnly} />

</>

);

};

src/components/ProductCategoryRow.tsx

type Props = {

category: string;

};

export const ProductCategoryRow: React.FC<Props> = ({ category }) => {

return (

<tr>

<th colSpan={2}>{category}</th>

</tr>

);

};

src/components/ProductRow.tsx

import type { Product } from '../types/ProductType';

type Props = {

product: Product;

};

export const ProductRow: React.FC<Props> = ({ product }) => {

const name = product.stocked ? (

product.name

) : (

<span style={{ color: 'red' }}>{product.name}</span>

);

return (

<tr>

<td>{name}</td>

<td>{product.price}</td>

</tr>

);

};

src/components/ProductTable.tsx

import { ProductCategoryRow } from './ProductCategoryRow';

import { ProductRow } from './ProductRow';

import type { Product } from '../types/ProductType';

type Props = {

products: Product[];

filterText: string;

inStockOnly: boolean;

};

export const ProductTable: React.FC<Props> = ({ products, filterText, inStockOnly }) => {

const rows: JSX.Element[] = [];

let lastCategory: string | null = null;

products.forEach((product) => {

if (product.name.toLowerCase().indexOf(filterText.toLowerCase()) === -1) {

return;

}

if (inStockOnly && !product.stocked) {

return;

}

if (product.category !== lastCategory) {

rows.push(<ProductCategoryRow category={product.category} key={product.category} />);

}

rows.push(<ProductRow product={product} key={product.name} />);

lastCategory = product.category;

});

return (

<table>

<thead>

<tr>

<th>Name</th>

<th>Price</th>

</tr>

</thead>

<tbody>{rows}</tbody>

</table>

);

};

src/components/SearchBar.tsx

import React from 'react';

type Props = {

filterText: string;

inStockOnly: boolean;

onFilterTextChange: React.Dispatch<React.SetStateAction<string>>;

onInStockOnlyChange: React.Dispatch<React.SetStateAction<boolean>>;

};

export const SearchBar: React.FC<Props> = ({

filterText,

inStockOnly,

onFilterTextChange,

onInStockOnlyChange,

}) => {

return (

<form>

<input

type="text"

value={filterText}

placeholder="Search..."

onChange={(e) => onFilterTextChange(e.target.value)}

/>

<label>

<input

type="checkbox"

checked={inStockOnly}

onChange={(e) => onInStockOnlyChange(e.target.checked)}

/>

Only show products in stock

</label>

</form>

);

};

src/types/ProductType.ts

export type Product = {

category: string;

price: string;

stocked: boolean;

name: string;

};

src/App.tsx

import { FilterableProductTable } from './components/FilterableProductTable';

const PRODUCTS = [

{ category: 'Fruits', price: '$1', stocked: true, name: 'Apple' },

{ category: 'Fruits', price: '$1', stocked: true, name: 'Dragonfruit' },

{ category: 'Fruits', price: '$2', stocked: false, name: 'Passionfruit' },

{ category: 'Vegetables', price: '$2', stocked: true, name: 'Spinach' },

{ category: 'Vegetables', price: '$4', stocked: false, name: 'Pumpkin' },

{ category: 'Vegetables', price: '$1', stocked: true, name: 'Peas' },

];

export const App = () => {

return (

<>

<FilterableProductTable products={PRODUCTS} />

</>

);

};

src/index.tsx

import React from 'react';

import ReactDOM from 'react-dom/client';

import './index.css';

import { App } from './App';

import reportWebVitals from './reportWebVitals';

const root = ReactDOM.createRoot(

document.getElementById('root') as HTMLElement

);

root.render(

<React.StrictMode>

<App />

</React.StrictMode>

);

// If you want to start measuring performance in your app, pass a function

// to log results (for example: reportWebVitals(console.log))

// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals

reportWebVitals();

最後に

こういう簡単なものからReactとTypeScriptの組み合わせを学習していくのが
ハードルが低く、おすすめです。

参考

React Docs BETA( https://beta.reactjs.org/ )
Thinking in React( https://beta.reactjs.org/learn/thinking-in-react )