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How to filter object array in React

movies = [
   {
    id:1,
    title: "movie1",
    genre:["action","sci-fi"],
    country:["usa","uk"]
   },
   {
    id:2,
    title: "movie2",
    genre:["action","comedy"],
    country:["usa","ireland"]
   },
   {
    id:3,
    title: "movie3",
    genre:["comedy","romance"],
    country:["ireland","uk]
   },
]

I want to filter movies by genre and country. I can do that in a very weird method. But I wonder what’s the shortcut of filtering. Is there any option that I can filter if the prop or props exist, if not leave the original?

const Component = ({ genre, country }) => {
  const [movies,setMovies]=useState([]);
  const [filteredMovies,setFilteredMovies]=useState([])

    useEffect(()=>{
    //fetch from api and set movies
  },[])
  
  useEffect(()=>{
    setFilteredMovies(
      movies.filter((item) =>
        {
           if(genre || country){
              if(!country){
                 return item.genre.includes(genre)
              }elseif(!genre){
                 return item.country.includes(country)
              }else{
                 return item.genre.includes(genre) && item.country.includes(country)
              }
           }else return item
        }
      )
    );
  },[movies,genre,country])

  return (
    <div>
      {filteredMovies.map((item) => (
        <Movie item={item} key={item.id} />
      ))}
    </div>
  );
}

Answer

Rearrange your data in a way that allows you to enter a single value or object which can be used to filter the data in the movies. For example if you’d arrange your filter like this: (which you kind of already if you wouldn’t destructure)

const filters = {
  genre: 'action',
  country: 'ireland'
};

Then you could loop over each movie and use the properties of the filters to access only the properties of a movie that you would like to check, like the pseudo-code below.

movie[property].includes(value)

When doing this you can leave out, or add any filter that you’d like.

Do be aware that in the current state the snippet below assumes that it only has to work with an array.

const filters = {
  genre: 'action',
  country: 'ireland'
};
  
const movies = [
  {
    id: 1,
    title: "movie1",
    genre: ["action", "sci-fi"],
    country: ["usa", "uk"]
  },
  {
    id: 2,
    title: "movie2",
    genre: ["action", "comedy"],
    country: ["usa", "ireland"]
  },
  {
    id: 3,
    title: "movie3",
    genre: ["comedy", "romance"],
    country: ["ireland", "uk"],
  },
];

const filterMovies = (movies, filters) =>
  movies.filter(movie => 
    Object.entries(filters).every(([key, value]) => 
      movie[key].includes(value)
    )
  )

const result = filterMovies(movies, filters);
console.log(result);