ReactのAPI練習用に。

index.js

import React from "react";
import ReactDOM from "react-dom";
import axios from "axios";
import Search from "./Search";

class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      postsList: []
    };

    this.handleClick = this.handleClick.bind(this);
    this.renderImageList = this.renderImageList.bind(this);
  }

  handleClick(target) {
    const search = target;
    const limit = 20;
    const url = `https://qiita.com/api/v2/items?page=1&per_page=${limit}&query=${search}`;
    axios
      .get(url, {
        headers: {
          Authorization: "Bearer 0a499cd45f8b05c01ec95e4b852f6e91d0dfff44"
        }
      })
      .then((res) => {
        this.setState({ postsList: res.data });
      })
      .catch(console.error);
  }

  renderImageList(list) {
    const posts = list.map((item, index) => {
      return (
        <li className="item" key={index}>
          <span>{index}: </span>
          <a href={item.url}>{item.title}</a>
        </li>
      );
    });
    return posts;
  }

  render() {
    return (
      <div>
        <Search search={this.handleClick} />
        <ul>{this.renderImageList(this.state.postsList)}</ul>
      </div>
    );
  }
}
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);

Search.js


import React from "react";

class Search extends React.Component {
  constructor(props) {
    super(props);
    this.state = { title: "" };
  }

  render() {
    return (
      <div>
        <h2>Find Qiita</h2>
        <form onSubmit={this.handleSubmit}>
          <input
            value={this.state.title}
            type="text"
            onChange={this.handleChange}
          />
          <input type="submit" value="Search" />
        </form>
      </div>
    );
  }

  // valueが変更された際に実行
  handleChange = (event) => {
    // 変更したvalueが返ってくる
    const title = event.target.value;
    // stateを変更
    this.setState({ title: title });
  };

  // submitされた際に実行
  handleSubmit = (event) => {
    event.preventDefault(); // ページ遷移防止
    // 受け取ったメソッドを実行し、app の state を変更している
    this.props.search(this.state.title);
    this.setState({ title: "" }); // submit後は、titleを空にする
  };
}
export default Search;