The Filter Project
TLDR
@mcabreradev/filterfiltering arrays is really easy.
This project provides a comprehensive implementation of a filter function in TypeScript. The filter function is a versatile tool that can be used to select a subset of items from an array based on a provided predicate function or expression.
The filter function in this project is designed to handle a wide variety of use cases. It can filter arrays of primitive values, objects, and even nested objects. The function also supports complex filtering expressions, including wildcard characters and regular expressions.
Whether you need to filter an array in a complex way, or you're just interested in understanding how a robust filter function can be implemented, this project is a valuable resource.
Installation
You can install this package using various package managers. Here are the commands for each of them:
npm
npm install @mcabreradev/filter
Usage
After installation, you can import the filter function from the package like this:
import filter from '@mcabreradev/filter';
If you're working in a Node.js environment, the installation process is the same as mentioned before. However, you can use the CommonJS syntax to import the filter function:
const filter = require('@mcabreradev/filter');
Features
The filter function in the provided TypeScript code is a versatile function that allows you to select a subset of items from an array based on a variety of conditions. Here are some of its key features:
Array Filtering:
The primary purpose of the filter function is to filter an array. It takes an array and a predicate function as arguments, and returns a new array that includes only the items for which the predicate function returns true.
import filter from '@mcabreradev/filter';
const numbers = [1, 2, 3, 4, 5];
const evenNumbers = filter(numbers, (n) => n % 2 === 0);
console.log(evenNumbers); // Output: [2, 4]
Case-Insensitive Search:
The filter function supports case-insensitive search. When you provide a string as the predicate, it will match any property of the objects in the array that contains the string, regardless of case.
import filter from '@mcabreradev/filter';
const words = ['Apple', 'Banana', 'Cherry'];
const result = filter(words, 'a');
console.log(result); // Output: ['Apple', 'Banana']
Wildcard Matching:
The filter function supports wildcard matching with the % and _ characters. The % character matches any sequence of characters, and the _ character matches any single character. These wildcards also work in a case-insensitive manner.
import filter from '@mcabreradev/filter';
const words = ['Apple', 'Banana', 'Cherry'];
const result = filter(words, 'A%e');
console.log(result); // Output: ['Apple']
Multiple Conditions:
The filter function allows you to filter an array based on multiple conditions. You can specify these conditions as an object, where each key-value pair represents a condition that the items in the array must meet to be included in the result.
import filter from '@mcabreradev/filter';
const users = [
{ name: 'Alice', age: 20 },
{ name: 'Bob', age: 25 },
{ name: 'Charlie', age: 30 },
];
const result = filter(users, { name: 'A%', age: 20 });
console.log(result); // Output: [{ name: 'Alice', age: 20 }]
Custom Predicate Functions:
The filter function allows you to provide a custom predicate function to determine which items should be included in the result. This gives you maximum flexibility to define your own conditions for filtering the array.
import filter from '@mcabreradev/filter';
const numbers = [1, 2, 3, 4, 5];
const result = filter(numbers, (n) => n > 3);
console.log(result); // Output: [4, 5]
Deep Comparison:
The filter function supports deep comparison of objects. This means that it can compare the properties of nested objects, not just the top-level properties.
import filter from '@mcabreradev/filter';
const users = [
{ name: 'Alice', age: 20, address: { city: 'New York' } },
{ name: 'Bob', age: 25, address: { city: 'Los Angeles' } },
{ name: 'Charlie', age: 30, address: { city: 'Chicago' } },
];
const result = filter(users, { address: { city: 'New York' } });
console.log(result); // Output: [{ name: 'Alice', age: 20, address: { city: 'New York' } }]
Negation:
The filter function supports negation. If the predicate is a string that starts with !, the function will include an item in the result only if it does not match the rest of the string.
import filter from '@mcabreradev/filter';
const words = ['Apple', 'Banana', 'Cherry'];
const result = filter(words, '!Apple');
console.log(result); // Output: ['Banana', 'Cherry']
Nested Objects:
The filter function can filter arrays with a nested object that has 2 node levels:
import filter from '@mcabreradev/filter';
const users = [
{ name: 'Alice', age: 20, address: { city: 'New York', country: 'USA' } },
{ name: 'Bob', age: 25, address: { city: 'Los Angeles', country: 'USA' } },
{ name: 'Charlie', age: 30, address: { city: 'London', country: 'UK' } },
];
const result = filter(users, { address: { country: 'USA' } });
console.log(result);
// Output:
//[
// { name: 'Alice', age: 20, address: { city: 'New York', country: 'USA' } },
// { name: 'Bob', age: 25, address: { city: 'Los Angeles', country: 'USA' } }
//]
And here's an example of filter function with a nested object that has 3 node levels:
import filter from '@mcabreradev/filter';
const users = [
{
name: 'Alice',
age: 20,
address: {
city: 'New York',
country: 'USA',
coordinates: { lat: 40.7128, long: 74.006 },
},
},
{
name: 'Bob',
age: 25,
address: {
city: 'Los Angeles',
country: 'USA',
coordinates: { lat: 34.0522, long: 118.2437 },
},
},
{
name: 'Charlie',
age: 30,
address: {
city: 'London',
country: 'UK',
coordinates: { lat: 51.5074, long: 0.1278 },
},
},
];
const result = filter(users, { address: { coordinates: { lat: 40.7128 } } });
console.log(result);
// Output:
// [{
// name: 'Alice',
// age: 20,
// address: {
// city: 'New York',
// country: 'USA',
// coordinates: {
// lat: 40.7128,
// long: 74.0060
// }
// }
// }]
Advanced Examples of Use
The filter function can be used in a wide variety of scenarios. Here are some examples of how it can be used:
Filters customers with a specific city
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, 'Berlin');
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
Filters customers with a specific city with wildcard %
The % wildcard represents any number of characters, even zero characters.
return all customers that contains the pattern 'erlin':
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, '%erlin');
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
return all customers that contains the pattern "Ber":
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, 'Ber%');
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
return all customers that contains the pattern "erli":
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, '%erli%');
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
Filters customers with a specific city with wildcard _
The _ wildcard represents a single character. It can be any character or number, but each _ represents one, and only one, character.
return all customers with a City starting with any character, followed by "erlin":
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, '_erlin');
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
return all customers with a City witch contains "erli":
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, '_erli_');
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
return all customers with a City starting with "L", followed by any 2 characters, ending with "lin":
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, 'B__lin');
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
Filters customers based on objects
return all customers with a City named "Berlin":
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, { city: 'Berlin' });
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
Filters customers based on object key value with wilcards %
return all customers with a City witch contains "erlin" at the end of the string:
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, { city: '%erlin' });
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
return all customers with a City witch contains "erli" at the begining of the string:
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, { city: 'Berl%' });
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
return all customers with a City witch contains "erlin" at the end of the string:
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, { city: '_erlin' });
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
return all customers with a City witch contains "erl" in the string:
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, { city: '_erl__' });
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
return all customers with a City witch contains the characters "e,li" in the string:
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, { city: '_e_li_' });
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
Filters customers based on a predicate function
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, ({ city }) => city === 'Berlin');
// Output:
// [{ name: 'Alfreds Futterkiste', city: 'Berlin' }]
Filters customers based on based on two cities
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, ({ city }) => city === 'Berlin' || city === 'London');
// Output:
// [
// { name: 'Alfreds Futterkiste', city: 'Berlin' },
// { name: 'Around the Horn', city: 'London' },
// { name: 'Bs Beverages', city: 'London' }
// ]
Filters customers based on based on two cities if exists
import filter from '@mcabreradev/filter';
const customers = [
{ name: 'Alfreds Futterkiste', city: 'Berlin' },
{ name: 'Around the Horn', city: 'London' },
{ name: "B's Beverages", city: 'London' },
{ name: 'Bolido Comidas preparadas', city: 'Madrid' },
{ name: 'Bon app', city: 'Marseille' },
{ name: 'Bottom-Dollar Marketse', city: 'Tsawassen' },
{ name: 'Cactus Comidas para llevar', city: 'Buenos Aires' },
];
filter(customers, ({ city }) => city === 'Berlin' && city === 'Caracas');
// Output:
// []
Looking for more?
You can take a look at my github repository https://github.com/mcabreradev/filter
Thanks..
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