Let's say I have this array of objects.

 const movieTitles = [
    {
      movieId: "4820",
      movieName: "The Planet Of The Apes",
    },
    {
      movieId: "0489",
      movieName: "Interstellar",
    },
    {
      movieId: "6238",
      movieName: "The Dark Knight",
    },
  ];

And an outside variable (that matches with the object with the Interstellar movie) const matchId = "0489";

My questions are:

1. How could I check the array for the correct object that contains the matchId variable?

2. How could I get that object and use it's properties (like movieName) once the ids have been confirmed to be the same?

3. If the variable dynamically changed, how could I check whatever the variable is against the array of objects to check whether it does or doesn't match?

Thanks for the help in advance!

CodePudding user response：

If each movieId is unique, then you should use an object, not an array. Something like this is better:

const movieTitles = {
  "4820": {
    movieName: "The Planet Of The Apes",
  },
  "0489": {
    movieName: "Interstellar",
  },
  "6238": {
    movieName: "The Dark Knight",
  },
};

Note: If you cannot change the format movieTitles, then you can create a new object from the original array like this:

const movieTitles = [{
    movieId: "4820",
    movieName: "The Planet Of The Apes",
  },
  {
    movieId: "0489",
    movieName: "Interstellar",
  },
  {
    movieId: "6238",
    movieName: "The Dark Knight",
  },
];

const movieObject = {};
for (const movie of movieTitles) {
  const id = movie.movieId;
  delete movie.movieId;
  movieObject[id] = movie;
}

console.log(movieObject);

Either way you do it, you can then easily select the movie you need with the syntax movies[movieId]. Like this:

const movies = {
  "4820": {
    movieName: "The Planet Of The Apes",
  },
  "0489": {
    movieName: "Interstellar",
  },
  "6238": {
    movieName: "The Dark Knight",
  },
};

// You can use a static value, like this:
console.log(movies["0489"])

// Or a variable like this:
const movieId = "4820"; // change this to any movie ID
console.log(movies[movieId])

This is much faster than looping over the array and much more idiomatic. The time complexity of using an object is a one-time conversion of O(n), then O(1) for each access after that. In contrast, using .filter() is O(n) every time.

CodePudding user response：

Javascript array function filter would be the perfect fit to solve in your situation.

function hasItem(checkItem){
let isAvailable = movieTitles.filter((item)=> item.movieId==checkItem)
return isAvailable
}

console.log(hasItem('0489'))

//returns {
//     movieId: "0489",
//      movieName: "Interstellar",
//    }

The isAvailable will have the array of the condition matched.