我对反应还很陌生，我正在开发一个组件，该组件将从本地 JSON 文件中获取数据并将其输出到表组件。
我目前卡在加载屏幕上，出现以下错误，未捕获（承诺）SyntaxError: Unexpected token < in JSON at position 0
我的第一个想法是 JSON 文件可能已损坏，我已经使用 JSON lint 测试了 JSON 文件并且它是有效的。
App.js
import React, { useEffect, useState, useMemo } from "react";
import './App.css';
import Search from './components/Search'
import TableHeader from './components/Header'
import Pagination from './components/Pagination'
import useFullPageLoader from "./hooks/useFullPageLoader";
import mockData from './MOCK_DATA.json';
function App() {
const [details, setDetails] = useState([]);
const [loader, showLoader, hideLoader] = useFullPageLoader();
const [totalItems, setTotalItems] = useState(0);
const [currentPage, setCurrentPage] = useState(1);
const [search, setSearch] = useState("");
const [sorting, setSorting] = useState({ field: "", order: "" });
const ITEMS_PER_PAGE = 50;
const headers = [
{ name: "id", field: "id", sortable: false },
{ name: "first_name", field: "first_name", sortable: true },
{ name: "last_name", field: "last_name", sortable: true },
{ name: "email", field: "email", sortable: false },
{ name: "gender", field: "gender", sortable: false },
{ name: "ip_address", field: "ip_address", sortable: false }
];
useEffect(() => {
const getData = () => {
showLoader();
fetch(mockData)
.then(response => response.json())
.then(json => {
hideLoader();
setDetails(json);
});
};
getData();
}, []);
const detailsData = useMemo(() => {
let computedDetails = details;
if (search) {
computedDetails = computedDetails.filter(
detail =>
detail.first_name.toLowerCase().includes(search.toLowerCase()) ||
detail.last_name.toLowerCase().includes(search.toLowerCase())
);
}
setTotalItems(computedDetails.length);
//Sorting comments
if (sorting.field) {
const reversed = sorting.order === "asc" ? 1 : -1;
computedDetails = computedDetails.sort(
(a, b) =>
reversed * a[sorting.field].localeCompare(b[sorting.field])
);
}
//Current Page slice
return computedDetails.slice(
(currentPage - 1) * ITEMS_PER_PAGE,
(currentPage - 1) * ITEMS_PER_PAGE + ITEMS_PER_PAGE
);
}, [details, currentPage, search, sorting]);
return (
<div className="row w-100">
<div className="col mb-3 col-12 text-center">
<div className="row">
<div className="col-md-6">
<Pagination
total={totalItems}
itemsPerPage={ITEMS_PER_PAGE}
currentPage={currentPage}
onPageChange={page => setCurrentPage(page)}
/>
</div>
<div className="col-md-6 d-flex flex-row-reverse">
<Search
onSearch={value => {
setSearch(value);
setCurrentPage(1);
}}
/>
</div>
</div>
<table className="table table-striped">
<TableHeader
headers={headers}
onSorting={(field, order) =>
setSorting({ field, order })
}
/>
<tbody>
{detailsData.map(detail => (
<tr>
<th scope="row" key={detail.id}>
{detail.id}
</th>
<td>{detail.first_name}</td>
<td>{detail.last_name}</td>
<td>{detail.email}</td>
<td>{detail.gender}</td>
<td>{detail.ip_address}</td>
</tr>
))}
</tbody>
</table>
</div>
{loader}
</div>
);
};
export default App;
MOCK_DATA.json
[{"id":1,"first_name":"Felicdad","last_name":"McKimmie","email":"fmckimmie0@lycos.com","gender":"Agender","ip_address":"99.216.194.167"},
{"id":2,"first_name":"Reinald","last_name":"Capelen","email":"rcapelen1@e-recht24.de","gender":"Male","ip_address":"193.151.24.49"},
{"id":3,"first_name":"Francyne","last_name":"Sheers","email":"fsheers2@surveymonkey.com","gender":"Genderqueer","ip_address":"117.134.38.199"},
{"id":4,"first_name":"Luelle","last_name":"Reynold","email":"lreynold3@tumblr.com","gender":"Polygender","ip_address":"203.34.23.135"},
{"id":5,"first_name":"Ivy","last_name":"Perrottet","email":"iperrottet4@elpais.com","gender":"Bigender","ip_address":"106.12.116.189"},
{"id":6,"first_name":"Tobye","last_name":"Petyt","email":"tpetyt5@bbb.org","gender":"Polygender","ip_address":"225.146.16.182"},
{"id":7,"first_name":"Eliot","last_name":"Maginn","email":"emaginn6@state.tx.us","gender":"Bigender","ip_address":"193.19.188.237"},
{"id":8,"first_name":"Ciel","last_name":"Lucio","email":"clucio7@lulu.com","gender":"Polygender","ip_address":"249.65.61.1"},
{"id":9,"first_name":"Haslett","last_name":"Farris","email":"hfarris8@noaa.gov","gender":"Male","ip_address":"247.37.86.113"},
{"id":10,"first_name":"Sunshine","last_name":"Gascard","email":"sgascard9@netvibes.com","gender":"Non-binary","ip_address":"118.125.194.37"},
{"id":11,"first_name":"Dieter","last_name":"Marner","email":"dmarnera@springer.com","gender":"Female","ip_address":"212.250.147.88"},
{"id":12,"first_name":"Oliy","last_name":"Manicomb","email":"omanicombb@arizona.edu","gender":"Agender","ip_address":"166.17.214.135"},
{"id":13,"first_name":"Jacky","last_name":"Beidebeke","email":"jbeidebekec@wunderground.com","gender":"Female","ip_address":"75.17.95.9"},
{"id":14,"first_name":"Berton","last_name":"Juan","email":"bjuand@bandcamp.com","gender":"Bigender","ip_address":"254.215.187.1"},
{"id":15,"first_name":"Gerick","last_name":"Freezor","email":"gfreezore@vkontakte.ru","gender":"Agender","ip_address":"140.42.52.239"},
{"id":16,"first_name":"Adore","last_name":"Millichip","email":"amillichipf@php.net","gender":"Genderfluid","ip_address":"67.110.77.105"},
{"id":17,"first_name":"Clim","last_name":"Gribbon","email":"cgribbong@google.de","gender":"Female","ip_address":"109.101.93.221"},
{"id":18,"first_name":"Ozzy","last_name":"Harbert","email":"oharberth@yelp.com","gender":"Male","ip_address":"217.37.94.242"},
{"id":19,"first_name":"Zonnya","last_name":"Connock","email":"zconnocki@webnode.com","gender":"Genderfluid","ip_address":"112.216.14.43"},
{"id":20,"first_name":"Quincy","last_name":"Dorton","email":"qdortonj@jugem.jp","gender":"Genderqueer","ip_address":"112.2.53.222"}]
答案 0 :(得分：2)
fetch 需要一个 URL，以便从某个端点获取数据。
你给了它一个 JSON，它不知道如何处理它。如果您想使用虚假数据，您可以在 useEffect
const getData = () => {
showLoader();
Promise.resolve(mockData)
.then(json => {
hideLoader();
setDetails(json);
});
};