javascript - React.js：如何将道具传递给组件？

问题描述

我想让API 调用可重用并在其他组件中使用它的功能。我在Hook/index.js组件中获取API 。然后我想在另一个组件中遍历从 API 获取的数据，将其作为参数并在其他组件中使用。我有一个用于flag(img)的Flag/index.js组件，并且想要获取图像的 url 作为参数并在Flag/index.js组件中使用。任何帮助将不胜感激。在Hook/index.js我获取API


import React, { useState, useEffect } from "react";

import "./hook.scss";

export default function Hook(){
  const [data, setData] = useState([]);
  const [error, setError] = useState(null);
  const [search, setSearch] = useState("");
 
  const fetchData = () => {
    fetch("https://restcountries.eu/rest/v2/all")
      .then((res) => res.json())
      .then((result) => setData(result))
      .catch((err) => console.log("error"));
  };

  useEffect(() => {
    const searchResult = data && data.filter((item) => item.name.toLowerCase().includes(search));
    setSearch(searchResult);
  }, []);

  useEffect(() => {
    fetchData();
  }, []);


  return [data, error];
}

在 App.js 中，我通过 API 数据进行映射

import React, { useState }from "react";
import Header from "./components/Header";
import SearchBar from "./components/SearchBar";
import Flag from "./components/Flag";
import useCountries from "./Hooks";

import "./App.scss";

export default function App () => {
  const [data, error] = useCountries();

  
  return (
    <div className="App">
      <SearchBar />
      <Header />
      {data &&
        data.map((country) => (
          <div className="CountryList" key={country.name}>
            <div className="CountryListImg">
              <img src={country.flag} alt="" width="80px" /> if change here to flag={country.flag} I see link in browser
            </div>
            <div className="countryName">{country.name}</div>
            <div className="population">{country.population}</div>
            <div className="region">{country.region}</div>
            <div>
              {country.languages.map((language, languageIndex) => (
                <div key={languageIndex}>{language.name}</div>
              ))}
            </div>
          </div>
        ))}
      <useCountries />
    </div>
  );
  return [data, error]
}

而我的Flag/index.js组件，当然不起作用

import React from "react";

import "./flag.scss";

export default function Flag({flag}) {
  return (
    <div className="">
      <img src={flag} alt="" width="80px" />  
    </div>
  );
};

如何制作工作搜索栏。现在它在控制台中显示未定义

import React, {useState} from "react";


import "./SearchBar.scss";

export default function Searchbar({data}) {
    const [search, setSearch] = useState("");

   function handleChange(e) {
    setSearch(e.target.value);
  } 
console.log(data)
  return (
    <div className="SearchBar">
      <input
        className="input"
        type="text"
        placeholder="search country ..."
        value={data}
        onChange={handleChange}
      />

      {data && data.filter((item) => item.name.toLowerCase().includes(search))}
    </div>
  );
};

标签： javascriptreactjs

javascript - React.js：如何将道具传递给组件？

问题描述

解决方案

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