React JS Axios Response is not populating the array of objects returned by api. 响应返回了 20 个对象

Question

hope you are doing well. Im just using ReactJS and I utilized the axios request to get news from a third party API. Now, the API returned 20 different articles. So I tried to use the map function to map over and iterate over the 20 articles and to create 20 cards(I created a card component that the api info would populate into). There are 20 articles, which means that there should be 20 cards. However, only 1 card shows. Please see below for my code. Thanks!

[![// TrumpNews
import React, { useEffect, useState } from "react";
import "./TrumpNews.css";
import CardComponent from "./CardComponent";
import axios from "axios";

const TrumpNews = () => {
  const API_KEY = "0949535b152f400aa2a162ecc055021a";
  const \[news, setNews\] = useState(\[\]);

  console.log(news);

  useEffect(() => {
    var url =
      "http://newsapi.org/v2/everything?" +
      "q=Trump&" +
      "from=2020-11-12&" +
      "sortBy=popularity&" +
      "apiKey=*********";

    axios
      .get(url)
      .then(async (res) => {
        setNews(\[res.data.articles\]);
      })
      .catch((err) => console.log(err));
  }, \[\]);

  return (
    <div className="trumpNews">
      {news.map((item) => (
        <CardComponent item={item} />
      ))}
    </div>
  );
};

export default TrumpNews;


// CardComponent
import React from "react";
import { makeStyles } from "@material-ui/core/styles";
import Card from "@material-ui/core/Card";
import CardHeader from "@material-ui/core/CardHeader";

import IconButton from "@material-ui/core/IconButton";
import Typography from "@material-ui/core/Typography";
import { red } from "@material-ui/core/colors";
import FavoriteIcon from "@material-ui/icons/Favorite";
import ShareIcon from "@material-ui/icons/Share";
import ExpandMoreIcon from "@material-ui/icons/ExpandMore";
import MoreVertIcon from "@material-ui/icons/MoreVert";
import "./CardComponent.css";

const useStyles = makeStyles((theme) => ({
  root: {
    maxWidth: 345,
  },
  media: {
    height: 0,
    paddingTop: "56.25%", // 16:9
  },
  expand: {
    transform: "rotate(0deg)",
    marginLeft: "auto",
    transition: theme.transitions.create("transform", {
      duration: theme.transitions.duration.shortest,
    }),
  },
  expandOpen: {
    transform: "rotate(180deg)",
  },
  avatar: {
    backgroundColor: red\[500\],
  },
}));

const CardComponent = ({ item }) => {
  const classes = useStyles();

  console.log(item.author);

  return (
    <Card className={classes.root}>
      <CardHeader
        action={
          <IconButton aria-label="settings">
            <MoreVertIcon />
          </IconButton>
        }
        title={item.description}
        subheader="September 14, 2016"
      />
      <br />
      <br />
      <br />
      <br />
      <br />
      <br />
      <br />
      <br />
      <br />
      <br />
      <div>{item\[0\].author}</div>
      {item\[0\].title}
    </Card>
  );
};

export default CardComponent;][1]][1]

Answer 1

You're creating a two dimensional array when you set the result -

setNews([res.data.articles]);

articles is already an array, so you just need to set the state like this -

setNews(res.data.articles);

Answer 2

In the .then method in your example you are putting array in array, you do not need the square brackets here:

setNews(\[res.data.articles\]);

It should look like this:

setNews(res.data.articles);