[英]Passing “value” into provider using createContext in React JS
我是 React JS 的新手,我正在嘗試了解功能組件中的createContext()
。 所以,在這里我試圖將存儲在books
的當前 state 傳遞給提供者,但我想我做錯了什么。 你能幫我解決這個問題嗎?
上下文組件:
import React, { createContext, useState } from "react";
export const BookContext = createContext();
const BookContextProvider = (props) => {
const [books, setBooks] = useState([
{ title: "Book 1", id: 1 },
{ title: "Book 2", id: 2 },
{ title: "Book 3", id: 3 },
{ title: "Book 4", id: 4 },
]);
return (
<BookContext.Provider value={ books }> //<-- Doesn't work
{props.children}
</BookContext.Provider>
);
};
export default BookContextProvider;
我要使用上下文的組件:
import React, { useContext } from "react";
import { BookContext } from "../contexts/BookContext";
const BookList = () => {
const { books } = useContext(BookContext);
return (
<div>
<ul>
{books.map((book) => (
<li key={book.id}>
{book.title}
</li>
))}
</ul>
</div>
);
};
export default BookList;
您沒有將默認值傳遞給您的createContext()
。
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