[Bug]: The solution to the state-related challenges on the webpage appear to be incorrect.
還沒有人認領這個 Issue。
- 主要語言
- JavaScript
- 星號
- 11.8k
- 分支
- 7.9k
- 平均合併
- 1 天 11 小時
- 30 天內合併 PR
- 11
描述
Summary
In the documentation on the 'Learn' page, under the section 'Updating Arrays in State,' the solution for Challenge 2 appears to have a bug.
When using console.log to debug the solution, the counts in the product array do not match what is displayed on the screen.
Page
https://react.dev/learn/updating-arrays-in-state
Details
"According to the solution's description, when the '+' button is pressed, the count value in the initialProducts array should increment. However, logging the values to the console shows that the values on the screen differ from those in the array."
Solution with 2 extra lines for logging (App.js):
import { useState } from 'react';
const initialProducts = [{
id: 0,
name: 'Baklava',
count: 1,
}, {
id: 1,
name: 'Cheese',
count: 5,
}, {
id: 2,
name: 'Spaghetti',
count: 2,
}];
export default function ShoppingCart() {
const [
products,
setProducts
] = useState(initialProducts)
function handleIncreaseClick(productId) {
setProducts(products.map(product => {
if (product.id === productId) {
return {
...product,
count: product.count + 1
};
} else {
return product;
}
}))
// Next 2 lines are not parts of the solution.
// They were added to test the result.
console.log(initialProducts)
console.log(products)
}
function handleDecreaseClick(productId) {
let nextProducts = products.map(product => {
if (product.id === productId) {
return {
...product,
count: product.count - 1
};
} else {
return product;
}
});
nextProducts = nextProducts.filter(p =>
p.count > 0
);
setProducts(nextProducts)
}
return (
<ul>
{products.map(product => (
<li key={product.id}>
{product.name}
{' '}
(<b>{product.count}</b>)
<button onClick={() => {
handleIncreaseClick(product.id);
}}>
+
</button>
<button onClick={() => {
handleDecreaseClick(product.id);
}}>
–
</button>
</li>
))}
</ul>
);
}
貢獻指南
從這裡開始
- 先讀完整個 Issue,再讀專案的貢獻指南。
- 在 Issue 下留言說明你要接手 —— 這能避免兩個人做同樣的事。
- Fork 儲存庫,在一個分支上完成修改。
- 送出 Pull Request,並在描述裡引用這個 Issue 編號。
研究方向
開啟 Updating Arrays in State 頁面,使用提供的 App.js 範例重現 Challenge 2,並比較主控台輸出與所呈現的計數。判斷解決方案或其說明是否不正確;當文件中的 challenge 產生一致的狀態與顯示結果時,即表示完成。
由索引模型根據 Issue 內容生成。
評估
- 技術堆疊
- javascript, react
- 領域
- documentation
- Issue 類型
- 缺陷
- 難度
- 2/5
- 預估耗時
- 1-3 小時
- 活躍度
- 停滯
- 描述清晰度
- 基本清楚
- 新手友好度
- 45/100