Filters an array of objects with multiple match-criteria.

arrayFilterFactory.1.ts

type FilterOperator = 'AND' | 'OR';
type FiltersBy<T> = {
  [K in keyof T]?: (value: T[K]) => boolean;
};

/**
 * Factory function that creates a specialized function to filter
 * arrays, by validating all filters (AND operator),
 * or validating just one of the filters (OR operator).
 * @param operator Method to validate all filters: AND, OR
 * @returns Specialized function
 */
function arrayFilterFactory(operator: FilterOperator) {
  const method = operator === 'AND' ? 'every' : 'some';

  /**
   * Filters an array of objects using custom predicates.
   * @param array List of elements to filter
   * @param filters Object with predicates as filters
   * @returns Filtered array
   */
  return function filterArrayBy<T>(array: T[], filters: FiltersBy<T>): T[] {
    const filterKeys = Object.keys(filters);
    return array.filter(item => {
      // validates filters (AND|OR operator)
      return filterKeys[method](prop => {
        return filters[prop](item[prop]);
      });
    });
  };
}

arrayFilterFactory.2.test.ts

describe('Testing arrayFilterFactory()', () => {
  const arrayFilterEvery = arrayFilterFactory('AND');
  const arrayFilterSome = arrayFilterFactory('OR');

  type Person = {
    age: number;
    name: string;
    email: string;
    nation: string;
  };

  const users: Person[] = [
    {age: 28, name: 'John', email: '[email protected]', nation: 'USA'},
    {age: 38, name: 'Marlin', email: '[email protected]', nation: 'England'},
    {age: 35, name: 'Tom', email: '[email protected]', nation: 'England'},
    {age: 28, name: 'Mark', email: '[email protected]', nation: 'England'},
  ];

  it('should filter an array of objects validating just one of the filters', () => {
    // filters are applied using OR operator
    const filters: FiltersBy<Person> = {
      nation: country => country.toUpperCase() === 'USA',
      age: age => age < 30,
    };

    const expected: Person[] = [
      {age: 28, name: 'John', email: '[email protected]', nation: 'USA'},
      {age: 28, name: 'Mark', email: '[email protected]', nation: 'England'},
    ];

    const filtered = arrayFilterSome(users, filters);
    expect(filtered).toStrictEqual(expected);
  });

  it('should filter an array of objects validating all filters', () => {
    // filters are applied using OR operator
    const filters: FiltersBy<Person> = {
      age: age => age < 30,
      nation: country => country.toUpperCase() === 'USA',
    };

    const expected: Person[] = [
      {age: 28, name: 'John', email: '[email protected]', nation: 'USA'},
    ];

    const filtered = arrayFilterEvery(users, filters);
    expect(filtered).toStrictEqual(expected);
  });
});

filterArrayBy.1.ts

/**
 * Filters an array of objects using custom predicates.
 * @param array List of elements to filter
 * @param filters Object with predicates as filters
 * @returns Filtered array
 */
function filterArrayBy<T>(array: T[], filters: FiltersBy<T>): T[] {
  const filterKeys = Object.keys(filters);
  return array.filter(item => {
    // validates all filters (AND operator)
    return filterKeys.every(prop => {
      return filters[prop](item[prop]);
    });
  });
}

type FiltersBy<T> = {
  [K in keyof T]?: (value: T[K]) => boolean;
};

filterArrayBy.2.test.ts

type Product = {
  name: string;
  color: string;
  size: number;
  locations: string[];
  details: {length: number; width: number};
};

describe('Testing filterArrayBy()', () => {
  it('should filter an array of products by multiple properties', () => {
    const products: Product[] = [
      { name: 'A', color: 'Blue', size: 50, locations: ['USA', 'Europe'], details: { length: 20, width: 70 } },
      { name: 'B', color: 'Blue', size: 60, locations: [], details: { length: 20, width: 70 } },
      { name: 'C', color: 'Black', size: 70, locations: ['Japan'], details: { length: 20, width: 71 } },
      { name: 'D', color: 'Green', size: 50, locations: ['USA'], details: { length: 20, width: 71 } },
    ];

    // filters are applied using AND operator
    const filters: FiltersBy<Product> = {
      size: size => size === 50 || size === 70,
      color: color => ['blue', 'black'].includes(color.toLowerCase()),
      locations: locations => !!locations.find(c => ['japan', 'usa'].includes(c.toLowerCase())),
      details: details => details.length < 30 && details.width >= 70,
    };

    const expected: Product[] = [
      { name: 'A', color: 'Blue', size: 50, locations: ['USA', 'Europe'], details: { length: 20, width: 70 } },
      { name: 'C', color: 'Black', size: 70, locations: ['Japan'], details: { length: 20, width: 71 } },
    ];

    const filtered = filterArrayBy(products, filters);
    expect(filtered).toStrictEqual(expected);
  });
});

filterArrayByEq.1.ts

const value = <T>(v: T) => (typeof v === 'string' ? v.toUpperCase() : v);

/**
 * Filters an array of objects using a list of valid values.
 * @param array List of elements to filter
 * @param filters Object whith lists of valid values
 * @returns Filtered array
 */
function filterArrayByEq<T extends {[key: string]: unknown}>(
  array: T[],
  filters: FiltersByEq<T>,
): T[] {
  const filterKeys = Object.keys(filters);
  return array.filter(item => {
    // validates all filters (AND operator)
    return filterKeys.every(key => {
      // ignores empty filters
      if (!filters[key].length) return true;
      return filters[key].find(f => value(f) === value(item[key]));
    });
  });
}

type FiltersByEq<T> = {
  [K in keyof T]?: T[K][];
};

filterArrayByEq.2.test.ts

type Product = {
  name: string;
  color: string;
  size: number;
};

describe('Testing filterArrayByEq()', () => {
  it('should filter an array of objects using a list of valid values', () => {
    const products: Product[] = [
      {name: 'A', color: 'Blue', size: 50},
      {name: 'B', color: 'Blue', size: 60},
      {name: 'C', color: 'Black', size: 70},
      {name: 'D', color: 'Green', size: 50},
    ];

    // Filters are applied using AND operator.
    // Each filter uses a list of valid values, compared using === operator.
    // String values are not case-sensitive.
    const filters: FiltersByEq<Product> = {
      color: ['BLUE', 'black'],
      size: [70, 50],
    };

    const expected: Product[] = [
      {name: 'A', color: 'Blue', size: 50},
      {name: 'C', color: 'Black', size: 70},
    ];

    const filtered = filterArrayByEq(products, filters);
    expect(filtered).toStrictEqual(expected);
  });
});

Hello guys! Thank God I found this thread! You are saving lives!
By the way, when applying the filter, I run into the following problem: I have the price list (json file) where the prices are stored. When filtering by price, the filter ignores floating numbers. Could you tell please how to fix it?
So my json looks like this:

const hotels = [
  {id: 1, name: '4 Seasons', price: 120.7, currency: 'USD', country: 'Canada'},
  {id: 2, name: 'Triton palm', price: 112, currency: 'USD', country: 'Canada'},
  {id: 3, name: 'Herrington place', price: 180, currency: 'USD', country: 'Poland'},
];

I tried to modify the filter like that:

function range(start, end) {
  start = parseFloat(start);
  end = parseFloat(end);
  return new Float32Array(end - start).fill().map((d, i) => i + start);
}

But it led me to nowhere :(

Full code I have:

const filterData = {
  country: ['Canada'],
  price: range(100, 150),
};

const value = v => (typeof v === 'string' ? v.toUpperCase() : v);

function filterPlainArray(array, filters) {
  const filterKeys = Object.keys(filters);

  return array.filter(item => {
    // validates all filters (AND operator)
    return filterKeys.every(key => {
      // ignores empty filters
      if (!filters[key].length) return true;
      return filters[key].find(filter => value(filter) === value(item[key]));
    });
  });
}

const filteredList = filterPlainArray(data, filterData);
console.log(filteredList);

(() => {

const hotels = [
  {"id":1, "name": "4 Seasons", "price":120.70, "currency":"USD", "country":"Canada"},
  {"id":2, "name": "Triton palm", "price":112, "currency":"USD", "country": "Canada"},
  {"id":3, "name": "Herrington place", "price":180, "currency":"USD", "country": "Poland"}
];

const keep_these_hotels = {
  country: ['Canada'],
  price: { min: 100, max: 150 }
};

const filter_function = (hotels) => {
  return hotels.filter((hotel) => {
    return Object.keys(keep_these_hotels).some((key) => {
      if (key === 'country'){
        return keep_these_hotels.country.some((country) => country === hotel.country);
      }
      if (key === 'price'){
        return hotel.price >= keep_these_hotels.price.min && hotel.price <= keep_these_hotels.price.max;
      }
    });
  })
}

console.log(filter_function(hotels));

})();

// The keep_these_hotels doesnt require for all conditions to be met, just one of them. Since you didn't mention that part I'm assumed it this way.

hello
thank you guys,
i have a small problem with this function

filterPlainArray(array, filters) { const filterKeys = Object.keys(filters); return array.filter(item => { // validates all filter criteria return filterKeys.some(key => { // ignores an empty filter if (!filters[key].length) return true; return filters[key](filter => filter === item[key]); }); }); }

when i set filters like this

var filterData = { typeTraitement:[0], typeExecution:[0], };

and
var dataArray =[ {"typeTraitement":0, "typeExecution": 1} {"typeTraitement":1, "typeExecution": 0} {"typeTraitement":2, "typeExecution": 0} }]

the result is null and is happing only win i filter with 0 the others values is correct
some one has any idea why this happing
thank you for help

Is it too hard to ask to give us a working example?

return filters[key](filter => filter === item[key]); }); }); } is not even valid syntax.

Is it too hard to ask to give us a working example?

return filters[key](filter => filter === item[key]); }); }); } is not even valid syntax.

thank you pro
I'm using TypeScript
here the syntax of function

filterPlainArray

function filterPlainArray(array, filters) {
  const filterKeys = Object.keys(filters);
  return array.filter(item => {
    return filterKeys.some(key => {
      if (!filters[key].length) return true;
      return filters[key].find(filter => filter === item[key]);
    });
  });
}

Filters data is:

const filters = {typeTraitement: [0], typeExecution: [0]};

and dataArray

const dataArray = [
  {typeTraitement: 0, typeExecution: 1},
  {typeTraitement: 1, typeExecution: 0},
  {typeTraitement: 2, typeExecution: 0},
  {typeTraitement: 2, typeExecution: 3},
];

-result is empty-

const result = this.filterPlainArray(dataArray, filters);

result:

expected result:

[
  {typeTraitement: 0, typeExecution: 1},
  {typeTraitement: 1, typeExecution: 0},
  {typeTraitement: 2, typeExecution: 0},
];

remark:

the function works fine with any number in filters other than 0

Question: What if the Value are multiple that is delimited by semicolon ";",

Sample Data :
Title multi value = "Station 1;Station 2"
Filter State = Station 1 //This is the user selected in a multi checkbox option

  const filterKeys = Object.keys(filters);
  return arr.filter(eachObj => {
    return filterKeys.every(eachKey => {
      if (!filters[eachKey].length) {
        return true; // passing an empty filter means that filter is ignored.
      }
      **return filters[eachKey].includes(eachObj[eachKey]);** 
      // The current behaviour, it only retrieves the exact data sample is "Station 1"= "Station 1"
    });
  });
};

@jherax -Great, thanks for this brainstorming thread.
I am struggling with nested keys in json to compare dynamically.

my data

{
  id: 1,
  user_status: 'ACTIVE',
  roles: [
    {id: 'APP_ADMIN', name: 'App Admin'},
    {id: 'APP_USER', name: 'App User'},
  ],
  permissions: {apps: ['abc', 'pqr']},
}

I am currently filtering it by user_status because it is straightforward, but need your help to make dynamic condition for roles and apps which is inside permission. How i can create condition for apps and roles.

@jherax - I can't ever shake your hand - but please accept this thank you so much for sharing this !
Cheers to writing better code with fewer headaches !

Hi foks, I am creating 2 level depth filtering(multi select check box) and need to filter out

• could you please suggest me the code.

• This is my filter file:
  

Hi foks, I am creating 2 level depth filtering(multi select check box) and need to filter out

• could you please suggest me the code.

Consider I have the below data:

[
{
    apId: "c3:89:6f:1a:83:5e",
    description: "Kiruna Ramp Beacon",
    estimated: false,
    externalId: null,
    id: 718311,
    name: "BLE_1",
    posX: 6622.404970932526,
    posY: 2834.686893101607,
    posZ: 3012.490824884788,
    timestamp: 0,
    type: "BLE_BEACON"
},
{
    apId: "e4:97:29:25:41:73",
    description: "Kiruna Ramp Beacon",
    estimated: false,
    externalId: null,
    id: 718312,
    name: "BLE_2",
    posX: 6401.213050968167,
    posY: 2791.9930699182455,
    posZ: 2983.5542385630656,
    timestamp: 0,
    type: "BLE_BEACON"
},
{
    apId: "ce:76:58:8c:66:e1",
    description: "Kiruna Ramp Beacon",
    estimated: false,
    externalId: null,
    id: 718313,
    name: "BLE_3",
    posX: 6175.356128422606,
    posY: 2863.5582614152468,
    posZ: 2956.701987555463,
    timestamp: 0,
    type: "BLE_BEACON"
}
]

Expected output is:

[
{
    apId: "c3:89:6f:1a:83:5e",
    description: "Kiruna Ramp Beacon",
    name: "BLE_1",
    posX: 6622.404970932526,
    posY: 2834.686893101607,
    posZ: 3012.490824884788,
    type: "BLE_BEACON",
},
{
    apId: "e4:97:29:25:41:73",
    description: "Kiruna Ramp Beacon",
    name: "BLE_2",
    posX: 6401.213050968167,
    posY: 2791.9930699182455,
    posZ: 2983.5542385630656,
    type: "BLE_BEACON",
},
{
    apId: "ce:76:58:8c:66:e1",
    description: "Kiruna Ramp Beacon",
    name: "BLE_3",
    posX: 6175.356128422606,
    posY: 2863.5582614152468,
    posZ: 2956.701987555463,
    type: "BLE_BEACON"
}
]

How to do it in TypeScript?

hey man! thank you a million!!! if you ever come to romania i'll buy you 10 beers!!!!!!!!!!!!!!!!!!!

Hey dude, thanks for sharing! Your snippet is handy so I can solve my problem related to filtering data using multiple criteria

Great code!
@estherjsuh where you able to solve it? I have the same problem....

I made a small lib to solve this problem
https://github.com/circa10a/filter-object-array

I have an array of Sizes which is Size = ["40","XL","43","M"]
This is what my Products JSON File looks like :

[{
    "productCatgoris": "womensfashion",
    "productSubCatgoris": "Kamiz",
    "productStoreName": "S-trade Store",
    "productId": "27",
    "productName": "Cotton Unstitched Salwar Kameez for Women - Pink",
    "productImage": "https://images.pexels.com/photos/15388429/pexels-photo-15388429.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
    "productPrice": "699",
    "productDiscount": "10",
    "offerStatus": false,
    "productBrand": "Strade",
    "ExpressDelivary": true,
    "FreeDelivary": true,
    "productStock": "60",
    "productSold": "10",
    "offerStartAndEnDate": "12-12-2021-01-04-2022",
    "offerName": "",
    "productDescription": ["Cotton Unstitched Salwar Kameez for Women - Pink"],
    "productSpecipication": {
      "Brand": "S-trade",
      "size": ["XL", "M", "L", "S", "2XL"],
      "gender": "Womens",
      "Color": ["Pink"]
    },
    "productShipping": "Dhaka city !!!! Feel free to buy from this site as we promise you same day delivery of any purchased items. Sookh helps you to purchase any goods or service with a very few steps. If you ever find any obligation of returning any purchased item or items, please review our Return & Refund Policy.",
    "productReviews": []
  },
  {
    "productCatgoris": "womensfashion",
    "productSubCatgoris": "Kamiz",
    "productStoreName": "S-trade Store",
    "productId": "28",
    "productName": "Cotton Unstitched Salwar Kameez for Women - Pink",
    "productImage": "https://images.pexels.com/photos/15388429/pexels-photo-15388429.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
    "productPrice": "699",
    "productDiscount": "10",
    "offerStatus": false,
    "productBrand": "Strade",
    "ExpressDelivary": false,
    "FreeDelivary": false,
    "productStock": "60",
    "productSold": "10",
    "offerStartAndEnDate": "12-12-2021-01-04-2022",
    "offerName": "",
    "productDescription": ["Cotton Unstitched Salwar Kameez for Women - Pink"],
    "productSpecipication": {
      "Brand": "S-trade",
      "size": ["41", "42", "43", "45"],
      "gender": "Womens",
      "Color": ["Pink"]
    },
    "productShipping": "Dhaka city !!!! Feel free to buy from this site as we promise you same day delivery of any purchased items. Sookh helps you to purchase any goods or service with a very few steps. If you ever find any obligation of returning any purchased item or items, please review our Return & Refund Policy.",
    "productReviews": []
  },
  {
    "productCatgoris": "womensfashion",
    "productSubCatgoris": "Kaftan",
    "productStoreName": "S-trade Store",
    "productId": "29",
    "productName": "Georgette Luxury Kaftan",
    "productImage": "https://images.pexels.com/photos/15388429/pexels-photo-15388429.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
    "productPrice": "699",
    "productDiscount": "10",
    "offerStatus": false,
    "productBrand": "Strade",
    "ExpressDelivary": true,
    "FreeDelivary": true,
    "productStock": "60",
    "productSold": "10",
    "offerStartAndEnDate": "12-12-2021-01-04-2022",
    "offerName": "",
    "productDescription": ["Georgette Luxury Kaftan"],
    "productSpecipication": {
      "Brand": "S-trade",
      "size": ["41", "42", "43", "45"],
      "gender": "Womens",
      "Color": ["Pink"]
    },
    "productShipping": "Dhaka city !!!! Feel free to buy from this site as we promise you same day delivery of any purchased items. Sookh helps you to purchase any goods or service with a very few steps. If you ever find any obligation of returning any purchased item or items, please review our Return & Refund Policy.",
    "productReviews": []
  },
  {
    "productCatgoris": "womensfashion",
    "productSubCatgoris": "Kaftan",
    "productStoreName": "S-trade Store",
    "productId": "30",
    "productName": "Georgette Luxury Kaftan",
    "productImage": "https://images.pexels.com/photos/15388429/pexels-photo-15388429.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
    "productPrice": "699",
    "productDiscount": "10",
    "offerStatus": false,
    "productBrand": "Strade",
    "ExpressDelivary": false,
    "FreeDelivary": false,
    "productStock": "60",
    "productSold": "10",
    "offerStartAndEnDate": "12-12-2021-01-04-2022",
    "offerName": "",
    "productDescription": ["Georgette Luxury Kaftan"],
    "productSpecipication": {
      "Brand": "S-trade",
      "size": ["41", "42", "43", "45"],
      "gender": "Womens",
      "Color": ["Pink"]
    },
    "productShipping": "Dhaka city !!!! Feel free to buy from this site as we promise you same day delivery of any purchased items. Sookh helps you to purchase any goods or service with a very few steps. If you ever find any obligation of returning any purchased item or items, please review our Return & Refund Policy.",
    "productReviews": []
  },
  {
    "productCatgoris": "womensfashion",
    "productSubCatgoris": "Kamiz",
    "productStoreName": "S-trade Store",
    "productId": "31",
    "productName": "Cotton Unstitched Salwar Kameez for Women - Pink",
    "productImage": "https://images.pexels.com/photos/15388429/pexels-photo-15388429.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1",
    "productPrice": "699",
    "productDiscount": "10",
    "offerStatus": false,
    "productBrand": "Strade",
    "ExpressDelivary": false,
    "FreeDelivary": false,
    "productStock": "60",
    "productSold": "10",
    "offerStartAndEnDate": "12-12-2021-01-04-2022",
    "offerName": "",
    "productDescription": ["Cotton Unstitched Salwar Kameez for Women - Pink"],
    "productSpecipication": {
      "Brand": "S-trade",
      "size": ["40", "41", "42", "43", "45"],
      "gender": "Womens",
      "Color": ["Pink"]
    },
    "productShipping": "Dhaka city !!!! Feel free to buy from this site as we promise you same day delivery of any purchased items. Sookh helps you to purchase any goods or service with a very few steps. If you ever find any obligation of returning any purchased item or items, please review our Return & Refund Policy.",
    "productReviews": []
  },
]

I have to find all products based on a given size array. That size needs to match the productSpecipication > Size[] array. if matched, it will return the particular products as a products array.