react count object properties in an array

Question

I am fetching data by an API. It is a movie, tv show, person database. When I search a word in the search box, it returns the related movie, tv show and person names in objects nested in an array. for example when I search "fight":

    [
    0:{original_name: "쌈 마이웨이", id: 70813, media_type: "tv", name: "Fight My Way", vote_count: 5,…}

    1:{vote_average: 8.2, vote_count: 8057, id: 550, video: false, media_type: "movie", title: "Fight Club",…}

    2:{vote_average: 6.1, vote_count: 215, id: 345922, video: false, media_type: "movie",…}

    3:{original_name: "Fight", id: 46554, media_type: "tv", name: "Fight", vote_count: 0, vote_average: 0,…}

    4:{original_name: "The Good Fight", id: 69158, media_type: "tv", name: "The Good Fight", vote_count: 22,…}

    5:{vote_average: 0, vote_count: 0, id: 158301, video: false, media_type: "movie", title: "Fight",…}
   ]

there are more results but I cut them. As you can see there are media_type properties in each object. there are 3 media types as you can understand (movie, tv, person). I want to count each type.

actually; I want the same thing in the link I guess: React: Syntax for calling setState in Switch Return

but it doesn't work for me. I tried to change simply the state of movieCount to 3 like this:

countType() {
        this.props.movies.map(movie => {
            return() => {
            if(movie.media_type === 'movie') {
                this.setState({ movieCount: 3});
                console.log(this.state);
            }
            }
        });
    }

but it doesn't work too.and I researched on the internet this stuff in javascript documentation and forums. not about just react. but I couldn't do anything. I know it's simple.

so how can I count objects in an array according to their property types?

Answer 1

Assuming that the data you fetched from API is stored in data variable, you can try the following code to find the count of movie media type in your data array:

const movies = data.filter(item => item.media_type === 'movie'));
const moviesCount = movies.length;

You can also dynamically calculate count of every media_type in your data array:

const mediaTypes = data
    .map(dataItem => dataItem.media_type) // get all media types
    .filter((mediaType, index, array) => array.indexOf(mediaType) === index); // filter out duplicates
  
const counts = mediaTypes
  .map(mediaType => ({
    type: mediaType,
    count: data.filter(item => item.media_type === mediaType).length
  }));

Then counts will be something like this:

[
  {
    "type": "tv",
    "count": 3
  },
  {
    "type": "movie",
    "count": 3
  }
]