Find object's property inside array using other property

Question

I'm trying to "link" the Genre property in each of these objects inside this array to the title property that outputs to the user inside value.

var movies= [{
    "Title": "Platoon",
    "Genre": "War"
}, {
    "Title": "Pulp Fiction",
    "Genre": "Crime"
}];

var name = value;
//console.log(name) outputs as title the user clicked on just fine

var genre = ...["Genre"]; //no idea how to go about this
//this should say genre = ["Genre"] in object where ["Title"] is same as value

Tried the IndexOf method to at least retrieve the element by searching for "Genre", but it outputs -1.

why not just iterate over the array and search for the title ? — Dhiraj
– Dhiraj, Commented Nov 2, 2016 at 15:56
I've read this five times, and I still don't get it? Do you want two arrays? — adeneo
– adeneo, Commented Nov 2, 2016 at 15:57
Can you include portion of javascript where value is set at user click event? — guest271314
– guest271314, Commented Nov 2, 2016 at 16:02

Nina Scholz · Accepted Answer · 2016-11-02 16:04:30Z

1

You could use Array#some.

function findGenre(title) {
    function search(a, i) {
        if (a.Title === title) {
            index = i;
            return true;
        }
    }
  
    var index;
    if (movies.some(search)) {
        return movies[index].Genre;
    }
}

var movies= [{ Title: "Platoon", Genre: "War" }, { Title: "Pulp Fiction", Genre: "Crime" }];

console.log(findGenre('Platoon'));

answered Nov 2, 2016 at 16:04

Nina Scholz

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2 Comments

TheNuttyStudent Over a year ago

This answer works for me but one question: If "Title" in the object had spaces, I mean if the property was "Movie Title" instead of "Title", how would you apply that change to (a.Title === title) as well?

Nina Scholz Over a year ago

you could use the bracket notation: a.['Movie Title'] === title. please have a look to property accessors.

Dhiraj · Accepted Answer · 2016-11-02 16:00:06Z

A simple for loop should do it.

var genre;
for(var i=0; i< movies.length; i++) {
  if (movies[i].Title === name) {
    genre = movies[i].Genre;
    break; // stop the loop assuming title is unique
  }
}

var movies= [{
    "Title": "Platoon",
    "Genre": "War"
}, {
    "Title": "Pulp Fiction",
    "Genre": "Crime"
}];

var name = 'Pulp Fiction';

var genre;
for(var i=0; i< movies.length; i++) {
  if (movies[i].Title === name) {
    genre = movies[i].Genre;
    break;
  }
}

alert(genre);

Daniel Conde Marin · Accepted Answer · 2016-11-02 16:02:51Z

0

You can do,

  var found = movies.filter(function(m) { 
     return m.Title === value 
  });

  if (found.length > 0) { 
    console.log(found[0].Genre); // or handle some way different if more than one match found 
  }

answered Nov 2, 2016 at 16:02

Daniel Conde Marin

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Comments

guest271314 · Accepted Answer · 2016-11-02 16:12:45Z

You can use for..of loop, object destructuring to get values by checking if .innerHTML of clicked element is equal to value of Title property of object

var movies= [{
    "Title": "Platoon",
    "Genre": "War"
}, {
    "Title": "Pulp Fiction",
    "Genre": "Crime"
}];

var divs = document.querySelectorAll("div");
var [value, genre] = [null, null];
for (let el of divs) {
  el.onclick = (e) => {
    for (let props of movies) {
      let {Title, Genre} = props;
      if (Title === e.target.innerHTML) {   
        [value, genre] = [Title, Genre];
        console.log(`value:${value}, genre:${genre}`);
        break;
      }
    }
  }
}

<div>Platoon</div>
<div>Pulp Fiction</div>

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