setState of many items React





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0















I am trying to build a news app that displays top 20 articles per country. However, I tried putting my setState call inside a loop but I quickly realized that they were being overwritten and the only one that would display is the last one. I was wondering how could I achieve this without overriding the previous entries. Thank you in advance!



//the following code is inside my App.js file and inside the App component
getNews = async (e) => {
e.preventDefault();
const country = e.target.elements.country.value;
const api_call = await fetch(this.buildURL(country));
const data = await api_call.json();

if (country) {
console.log(data);

//i changed this to just display the first article out of 20
this.setState({
title: data.articles[0].title,
image: data.articles[0].urlToImage,
description: data.articles[0].description,
author: data.articles[0].author,
link: data.articles[0].url,
err: ""
});
}
else {
this.setState({
title: undefined,
image: undefined,
description: undefined,
author: undefined,
link: undefined,
err: "Please enter valid country"
});
}


}

render() {
return(
<div>
<Titles />
<Form getNews={this.getNews}/>
<News title={this.state.title}
image={this.state.image}
description={this.state.description}
author={this.state.author}
link={this.state.link}
err={this.state.err}
/>
</div>
);
}


This is a beginners project so pls keep that in mind haha.










share|improve this question























  • What kind of response do you get from your API? can you edit the question so we can understand better?

    – Akar
    Nov 22 '18 at 19:58











  • Also, having a bit more of your app code helps. From the looks of it though I do not see anything looping over your response data to store articles, nor do I see in the render function some array map function to render the resultant array of articles.

    – Drew Reese
    Nov 22 '18 at 20:12




















0















I am trying to build a news app that displays top 20 articles per country. However, I tried putting my setState call inside a loop but I quickly realized that they were being overwritten and the only one that would display is the last one. I was wondering how could I achieve this without overriding the previous entries. Thank you in advance!



//the following code is inside my App.js file and inside the App component
getNews = async (e) => {
e.preventDefault();
const country = e.target.elements.country.value;
const api_call = await fetch(this.buildURL(country));
const data = await api_call.json();

if (country) {
console.log(data);

//i changed this to just display the first article out of 20
this.setState({
title: data.articles[0].title,
image: data.articles[0].urlToImage,
description: data.articles[0].description,
author: data.articles[0].author,
link: data.articles[0].url,
err: ""
});
}
else {
this.setState({
title: undefined,
image: undefined,
description: undefined,
author: undefined,
link: undefined,
err: "Please enter valid country"
});
}


}

render() {
return(
<div>
<Titles />
<Form getNews={this.getNews}/>
<News title={this.state.title}
image={this.state.image}
description={this.state.description}
author={this.state.author}
link={this.state.link}
err={this.state.err}
/>
</div>
);
}


This is a beginners project so pls keep that in mind haha.










share|improve this question























  • What kind of response do you get from your API? can you edit the question so we can understand better?

    – Akar
    Nov 22 '18 at 19:58











  • Also, having a bit more of your app code helps. From the looks of it though I do not see anything looping over your response data to store articles, nor do I see in the render function some array map function to render the resultant array of articles.

    – Drew Reese
    Nov 22 '18 at 20:12
















0












0








0


1






I am trying to build a news app that displays top 20 articles per country. However, I tried putting my setState call inside a loop but I quickly realized that they were being overwritten and the only one that would display is the last one. I was wondering how could I achieve this without overriding the previous entries. Thank you in advance!



//the following code is inside my App.js file and inside the App component
getNews = async (e) => {
e.preventDefault();
const country = e.target.elements.country.value;
const api_call = await fetch(this.buildURL(country));
const data = await api_call.json();

if (country) {
console.log(data);

//i changed this to just display the first article out of 20
this.setState({
title: data.articles[0].title,
image: data.articles[0].urlToImage,
description: data.articles[0].description,
author: data.articles[0].author,
link: data.articles[0].url,
err: ""
});
}
else {
this.setState({
title: undefined,
image: undefined,
description: undefined,
author: undefined,
link: undefined,
err: "Please enter valid country"
});
}


}

render() {
return(
<div>
<Titles />
<Form getNews={this.getNews}/>
<News title={this.state.title}
image={this.state.image}
description={this.state.description}
author={this.state.author}
link={this.state.link}
err={this.state.err}
/>
</div>
);
}


This is a beginners project so pls keep that in mind haha.










share|improve this question














I am trying to build a news app that displays top 20 articles per country. However, I tried putting my setState call inside a loop but I quickly realized that they were being overwritten and the only one that would display is the last one. I was wondering how could I achieve this without overriding the previous entries. Thank you in advance!



//the following code is inside my App.js file and inside the App component
getNews = async (e) => {
e.preventDefault();
const country = e.target.elements.country.value;
const api_call = await fetch(this.buildURL(country));
const data = await api_call.json();

if (country) {
console.log(data);

//i changed this to just display the first article out of 20
this.setState({
title: data.articles[0].title,
image: data.articles[0].urlToImage,
description: data.articles[0].description,
author: data.articles[0].author,
link: data.articles[0].url,
err: ""
});
}
else {
this.setState({
title: undefined,
image: undefined,
description: undefined,
author: undefined,
link: undefined,
err: "Please enter valid country"
});
}


}

render() {
return(
<div>
<Titles />
<Form getNews={this.getNews}/>
<News title={this.state.title}
image={this.state.image}
description={this.state.description}
author={this.state.author}
link={this.state.link}
err={this.state.err}
/>
</div>
);
}


This is a beginners project so pls keep that in mind haha.







javascript arrays json setstate






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 22 '18 at 19:54









lcchlcch

31




31













  • What kind of response do you get from your API? can you edit the question so we can understand better?

    – Akar
    Nov 22 '18 at 19:58











  • Also, having a bit more of your app code helps. From the looks of it though I do not see anything looping over your response data to store articles, nor do I see in the render function some array map function to render the resultant array of articles.

    – Drew Reese
    Nov 22 '18 at 20:12





















  • What kind of response do you get from your API? can you edit the question so we can understand better?

    – Akar
    Nov 22 '18 at 19:58











  • Also, having a bit more of your app code helps. From the looks of it though I do not see anything looping over your response data to store articles, nor do I see in the render function some array map function to render the resultant array of articles.

    – Drew Reese
    Nov 22 '18 at 20:12



















What kind of response do you get from your API? can you edit the question so we can understand better?

– Akar
Nov 22 '18 at 19:58





What kind of response do you get from your API? can you edit the question so we can understand better?

– Akar
Nov 22 '18 at 19:58













Also, having a bit more of your app code helps. From the looks of it though I do not see anything looping over your response data to store articles, nor do I see in the render function some array map function to render the resultant array of articles.

– Drew Reese
Nov 22 '18 at 20:12







Also, having a bit more of your app code helps. From the looks of it though I do not see anything looping over your response data to store articles, nor do I see in the render function some array map function to render the resultant array of articles.

– Drew Reese
Nov 22 '18 at 20:12














2 Answers
2






active

oldest

votes


















1














So you want include all news items in state, then loop over them and create a News element for each of them. Something like this for the request:



getNews = async e => {
e.preventDefault();
const country = e.target.elements.country.value;
if (!country) {
this.setState({
articles: null,
err: "Please enter valid country"
});
}
let data;
try {
data = await fetch(this.buildURL(country)).then(res => res.json());
} catch (error) {
this.setState({
articles: null,
err: "Please enter valid country"
});
}
if (data) {
this.setState({
articles: data.map(article => ({
title: article.title,
image: article.urlToImage,
description: article.description,
author: article.author,
link: article.url
}))
});
}
};


although I do not guarantee it is bug free!



Then when you have all articles in state, you can loop over them:



render() {
return (
<div>
<Titles />
<Form getNews={this.getNews} />

{this.state.articles.map(article => (
<News
title={article.title}
image={article.image}
description={this.state.description}
author={article.author}
link={article.link}
err={article.err}
/>
))}
</div>
);
}


or you can spread the props like this, if you know the object key names you stored in state match exactly those the News component expects:



  {this.state.articles.map(article => (
<News {...article}/>
))}





share|improve this answer































    0














    Your state should have an array instead of just provision for one object.



    this.setState({
    title: data.articles[0].title,
    image: data.articles[0].urlToImage,
    description: data.articles[0].description,
    author: data.articles[0].author,
    link: data.articles[0].url,
    err: ""
    });


    Should be changed to something like the following.



    var articles = this.state.articles.slice();
    var newArticle = {
    title: data.articles[0].title,
    image: data.articles[0].urlToImage,
    description: data.articles[0].description,
    author: data.articles[0].author,
    link: data.articles[0].url,
    err: ""
    };
    articles.push(newArticle);

    this.setState(articles);


    Also note that setState is asynchronous. So sometimes, you should use the existing state to determine the new value of state. Refer setState documentation






    share|improve this answer
























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      2 Answers
      2






      active

      oldest

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      2 Answers
      2






      active

      oldest

      votes









      active

      oldest

      votes






      active

      oldest

      votes









      1














      So you want include all news items in state, then loop over them and create a News element for each of them. Something like this for the request:



      getNews = async e => {
      e.preventDefault();
      const country = e.target.elements.country.value;
      if (!country) {
      this.setState({
      articles: null,
      err: "Please enter valid country"
      });
      }
      let data;
      try {
      data = await fetch(this.buildURL(country)).then(res => res.json());
      } catch (error) {
      this.setState({
      articles: null,
      err: "Please enter valid country"
      });
      }
      if (data) {
      this.setState({
      articles: data.map(article => ({
      title: article.title,
      image: article.urlToImage,
      description: article.description,
      author: article.author,
      link: article.url
      }))
      });
      }
      };


      although I do not guarantee it is bug free!



      Then when you have all articles in state, you can loop over them:



      render() {
      return (
      <div>
      <Titles />
      <Form getNews={this.getNews} />

      {this.state.articles.map(article => (
      <News
      title={article.title}
      image={article.image}
      description={this.state.description}
      author={article.author}
      link={article.link}
      err={article.err}
      />
      ))}
      </div>
      );
      }


      or you can spread the props like this, if you know the object key names you stored in state match exactly those the News component expects:



        {this.state.articles.map(article => (
      <News {...article}/>
      ))}





      share|improve this answer




























        1














        So you want include all news items in state, then loop over them and create a News element for each of them. Something like this for the request:



        getNews = async e => {
        e.preventDefault();
        const country = e.target.elements.country.value;
        if (!country) {
        this.setState({
        articles: null,
        err: "Please enter valid country"
        });
        }
        let data;
        try {
        data = await fetch(this.buildURL(country)).then(res => res.json());
        } catch (error) {
        this.setState({
        articles: null,
        err: "Please enter valid country"
        });
        }
        if (data) {
        this.setState({
        articles: data.map(article => ({
        title: article.title,
        image: article.urlToImage,
        description: article.description,
        author: article.author,
        link: article.url
        }))
        });
        }
        };


        although I do not guarantee it is bug free!



        Then when you have all articles in state, you can loop over them:



        render() {
        return (
        <div>
        <Titles />
        <Form getNews={this.getNews} />

        {this.state.articles.map(article => (
        <News
        title={article.title}
        image={article.image}
        description={this.state.description}
        author={article.author}
        link={article.link}
        err={article.err}
        />
        ))}
        </div>
        );
        }


        or you can spread the props like this, if you know the object key names you stored in state match exactly those the News component expects:



          {this.state.articles.map(article => (
        <News {...article}/>
        ))}





        share|improve this answer


























          1












          1








          1







          So you want include all news items in state, then loop over them and create a News element for each of them. Something like this for the request:



          getNews = async e => {
          e.preventDefault();
          const country = e.target.elements.country.value;
          if (!country) {
          this.setState({
          articles: null,
          err: "Please enter valid country"
          });
          }
          let data;
          try {
          data = await fetch(this.buildURL(country)).then(res => res.json());
          } catch (error) {
          this.setState({
          articles: null,
          err: "Please enter valid country"
          });
          }
          if (data) {
          this.setState({
          articles: data.map(article => ({
          title: article.title,
          image: article.urlToImage,
          description: article.description,
          author: article.author,
          link: article.url
          }))
          });
          }
          };


          although I do not guarantee it is bug free!



          Then when you have all articles in state, you can loop over them:



          render() {
          return (
          <div>
          <Titles />
          <Form getNews={this.getNews} />

          {this.state.articles.map(article => (
          <News
          title={article.title}
          image={article.image}
          description={this.state.description}
          author={article.author}
          link={article.link}
          err={article.err}
          />
          ))}
          </div>
          );
          }


          or you can spread the props like this, if you know the object key names you stored in state match exactly those the News component expects:



            {this.state.articles.map(article => (
          <News {...article}/>
          ))}





          share|improve this answer













          So you want include all news items in state, then loop over them and create a News element for each of them. Something like this for the request:



          getNews = async e => {
          e.preventDefault();
          const country = e.target.elements.country.value;
          if (!country) {
          this.setState({
          articles: null,
          err: "Please enter valid country"
          });
          }
          let data;
          try {
          data = await fetch(this.buildURL(country)).then(res => res.json());
          } catch (error) {
          this.setState({
          articles: null,
          err: "Please enter valid country"
          });
          }
          if (data) {
          this.setState({
          articles: data.map(article => ({
          title: article.title,
          image: article.urlToImage,
          description: article.description,
          author: article.author,
          link: article.url
          }))
          });
          }
          };


          although I do not guarantee it is bug free!



          Then when you have all articles in state, you can loop over them:



          render() {
          return (
          <div>
          <Titles />
          <Form getNews={this.getNews} />

          {this.state.articles.map(article => (
          <News
          title={article.title}
          image={article.image}
          description={this.state.description}
          author={article.author}
          link={article.link}
          err={article.err}
          />
          ))}
          </div>
          );
          }


          or you can spread the props like this, if you know the object key names you stored in state match exactly those the News component expects:



            {this.state.articles.map(article => (
          <News {...article}/>
          ))}






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 22 '18 at 21:31









          CecilCecil

          22625




          22625

























              0














              Your state should have an array instead of just provision for one object.



              this.setState({
              title: data.articles[0].title,
              image: data.articles[0].urlToImage,
              description: data.articles[0].description,
              author: data.articles[0].author,
              link: data.articles[0].url,
              err: ""
              });


              Should be changed to something like the following.



              var articles = this.state.articles.slice();
              var newArticle = {
              title: data.articles[0].title,
              image: data.articles[0].urlToImage,
              description: data.articles[0].description,
              author: data.articles[0].author,
              link: data.articles[0].url,
              err: ""
              };
              articles.push(newArticle);

              this.setState(articles);


              Also note that setState is asynchronous. So sometimes, you should use the existing state to determine the new value of state. Refer setState documentation






              share|improve this answer




























                0














                Your state should have an array instead of just provision for one object.



                this.setState({
                title: data.articles[0].title,
                image: data.articles[0].urlToImage,
                description: data.articles[0].description,
                author: data.articles[0].author,
                link: data.articles[0].url,
                err: ""
                });


                Should be changed to something like the following.



                var articles = this.state.articles.slice();
                var newArticle = {
                title: data.articles[0].title,
                image: data.articles[0].urlToImage,
                description: data.articles[0].description,
                author: data.articles[0].author,
                link: data.articles[0].url,
                err: ""
                };
                articles.push(newArticle);

                this.setState(articles);


                Also note that setState is asynchronous. So sometimes, you should use the existing state to determine the new value of state. Refer setState documentation






                share|improve this answer


























                  0












                  0








                  0







                  Your state should have an array instead of just provision for one object.



                  this.setState({
                  title: data.articles[0].title,
                  image: data.articles[0].urlToImage,
                  description: data.articles[0].description,
                  author: data.articles[0].author,
                  link: data.articles[0].url,
                  err: ""
                  });


                  Should be changed to something like the following.



                  var articles = this.state.articles.slice();
                  var newArticle = {
                  title: data.articles[0].title,
                  image: data.articles[0].urlToImage,
                  description: data.articles[0].description,
                  author: data.articles[0].author,
                  link: data.articles[0].url,
                  err: ""
                  };
                  articles.push(newArticle);

                  this.setState(articles);


                  Also note that setState is asynchronous. So sometimes, you should use the existing state to determine the new value of state. Refer setState documentation






                  share|improve this answer













                  Your state should have an array instead of just provision for one object.



                  this.setState({
                  title: data.articles[0].title,
                  image: data.articles[0].urlToImage,
                  description: data.articles[0].description,
                  author: data.articles[0].author,
                  link: data.articles[0].url,
                  err: ""
                  });


                  Should be changed to something like the following.



                  var articles = this.state.articles.slice();
                  var newArticle = {
                  title: data.articles[0].title,
                  image: data.articles[0].urlToImage,
                  description: data.articles[0].description,
                  author: data.articles[0].author,
                  link: data.articles[0].url,
                  err: ""
                  };
                  articles.push(newArticle);

                  this.setState(articles);


                  Also note that setState is asynchronous. So sometimes, you should use the existing state to determine the new value of state. Refer setState documentation







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered Nov 23 '18 at 12:23









                  xadhixxadhix

                  14711




                  14711






























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