Search for multiple filters in JSON using Javascript forEach and indexOf

Question

I have data in JSON format in which I need to perform search. There are different tags available and when I click on them it searches in JSON and returns the items which has those tags. For this I am using a js function. It works correctly for the first time but When I push second filter in the function it returns wrong data.

Available Filters are:

Binding

• Paperback
• Hardcover
• Audiobook
• Boxed Set

Category

• Classic Rock
• Pop
• Pop Rock
• Electro Pop
• Soft Rock
• Rock

Language

• German
• English
• French

Author

• Male
• Female
• Male/Female

Here is the JSON and code I am using:

var m = {
      "Books": [{
          "title": "Book 1",
          "binding": "paperback",
          "category": "pop",
          "language": "english",
          "author": "male"
        },
        {
          "title": "Book 2",
          "binding": "hardcover",
          "category": "pop rock,electro pop",
          "language": "french",
          "author": "female"
        },
        {
          "title": "Book 3",
          "binding": "audiobook",
          "category": "soft rock",
          "language": "german",
          "author": "male,female"
        },
        {
          "title": "Book 4",
          "binding": "boxed set",
          "category": "rock,classic rock",
          "language": "english",
          "author": "female,male"
        },
        {
          "title": "Book 5",
          "binding": "paperback",
          "category": "electro pop,rock,classic rock",
          "language": "french",
          "author": "male/female"
        },
        {
          "title": "Book 6",
          "binding": "paperback",
          "category": "rock",
          "language": "french",
          "author": "male"
        }
      ]
    }


    // a function which accepts key which is one of binding,category,language,author.
    // the array will be filtered on this key
    function getFilteredElement(key, value) {
        var bookFilter = [];
        m.Books.forEach(function(item){
           var getFilterField = item[key];
           // since the value is a string, so splitting it and creating an array
           var keyArray = item[key].split(',');
           // now checking if the passed value has a presence in the  above array
           if (keyArray.indexOf(value) !== -1) {
               // if present pushed the book name
               bookFilter.push(item.title);
           }
       });
        // returning the array of books
        return bookFilter;
    }

    console.log(getFilteredElement('category', 'rock'))

For e.g. When I push category = rock it returns Book 4, Book 5 and Book 6 but If I push category = rock and language = french, the returned result should only be Book 5 but it doesn't return correct results.

Could anyone please help.

Answer 1

You could use an object for filters and take the keys the key to search for and the value as excact value for the string.

Properties with commas are splitted and checked.

function getBooks(filters) {
    return array.Books.filter(function (o) {
        return Object.keys(filters).every(function (k) {
            return o[k].split(',').some(function (v) {
                return v === filters[k];
            });
        });
    });
    //.map(function (o) {
    //    return o.title;
    //});
}

var array = { Books: [{ title: "Book 1", binding: "paperback", category: "pop", language: "english", author: "male" }, { title: "Book 2", binding: "hardcover", category: "pop rock,electro pop", language: "french", author: "female" }, { title: "Book 3", binding: "audiobook", category: "soft rock", language: "german", author: "male,female" }, { title: "Book 4", binding: "boxed set", category: "rock,classic rock", language: "english", author: "female,male" }, { title: "Book 5", binding: "paperback", category: "electro pop,rock,classic rock", language: "french", author: "male/female" }, { title: "Book 6", binding: "paperback", category: "rock", language: "french", author: "male" }] };

console.log(getBooks({ category: 'rock' }));
console.log(getBooks({ category: 'rock', language: 'french' }));

.as-console-wrapper { max-height: 100% !important; top: 0; }

Answer 2

Use can utilize Array.prototype.filter(), Array.prototype.reduce(), and String.prototype.includes() to create such a filtration system, wherein an array of filters consisting of key value pairs can progressively be added to in order to refine an array of books.

See below for a practical example.

// Books.
const books = [
  {
    "title": "Book 1",
    "binding": "paperback",
    "category": "pop",
    "language": "english",
    "author": "male"
  },
  {
    "title": "Book 2",
    "binding": "hardcover",
    "category": "pop rock,electro pop",
    "language": "french",
    "author": "female"
  },
  {
    "title": "Book 3",
    "binding": "audiobook",
    "category": "soft rock",
    "language": "german",
    "author": "male,female"
  },
  {
    "title": "Book 4",
    "binding": "boxed set",
    "category": "rock,classic rock",
    "language": "english",
    "author": "female,male"
  },
  {
    "title": "Book 5",
    "binding": "paperback",
    "category": "electro pop,rock,classic rock",
    "language": "french",
    "author": "male/female"
  },
  {
    "title": "Book 6",
    "binding": "paperback",
    "category": "rock",
    "language": "french",
    "author": "male"
  }
]

// Query.
const query = (books, filters) => {

  // filters = [{key: 'category', value: 'string'}..]

  return books.filter((book) => {

    // Found?
    return filters.reduce((found, filter) => {
      if (!(book[filter.key].includes(filter.value))) return false
      return found
    }, true)

  })

}

// Log.
console.log('Category = Rock', query(books, [{key: 'category', value: 'rock'}]))
console.log('Category = Rock + Language = French', query(books, [{key: 'language', value: 'french'}]))

console.log('Paperback', query(books, [{key: 'binding', value: 'paperback'}])) // Paperback.
console.log('Paperback + Male', query(books, [{key: 'binding', value: 'paperback'}, {key: 'author', value: 'male'}])) // Paperback + Male.
console.log('Paperback + Male + Pop', query(books, [{key: 'binding', value: 'paperback'}, {key: 'author', value: 'male'}, {key: 'category', value: 'pop'}])) // Paperback + Male + Pop.