Javascript Extensions

Custom JavaScript Array and String Extensions

This repository contains custom extensions for JavaScript’s Array and String prototypes, providing additional utility functions.

String Prototype Extension

• capitalizeFirstLetter: Capitalizes the first letter of a string.

Array Prototype Extensions

• groupBy(callback): Groups array elements based on the provided callback.
• groupByKey(keyName): Groups array of objects by a specific key.
• distinct(): Returns an array with distinct elements.
• distinctByKey(key): Returns an array of unique objects based on a specific key.
• sortBy(callback): Sorts the array based on a custom callback function.
• sortByKey(key): Sorts the array of objects based on a specific key.
• sum(callback): Computes the sum of an array based on a callback function.
• sumByKey(key): Computes the sum of an array of objects based on a specific key.
• chunk(size): Splits the array into chunks of a specified size.
• unique(): Returns an array with unique elements.
• uniqueBy(key): Returns an array of unique objects based on a specific key.
• remove(item): Removes a specific item from the array.
• removeByKeyValue(key, value): Removes items based on a specific key-value pair.
• findIndexByKeyValue(key, value): Finds the index of an object based on a specific key-value pair.
• findKeyValue(key, value): Finds an object based on a specific key-value pair.
• findValueByKeyValue(key, value, retrieveKey): Finds the value of a specific key in an object based on another key-value pair.

Get Abhishek Vishwakarma’s stories in your inbox

Join Medium for free to get updates from this writer.

Remember me for faster sign in

Usage

Import the JavaScript extension script before using any of the provided functions. This script adds custom functionality to the String and Array prototypes.

<script src="https://cdn.jsdelivr.net/gh/abhigdrv/javascript-extension/js-extension.js"></script>

Example Usage:

// Capitalize the first letter of a string
const capitalizedString = "hello".capitalizeFirstLetter();
console.log(capitalizedString); // Outputs: Hello
// Group array elements based on a custom callback
const numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9];
const groupedByOddEven = numbers.groupBy((num) =>
  num % 2 === 0 ? "even" : "odd"
);
console.log(groupedByOddEven);
/*
  Outputs:
  {
    'odd': [1, 3, 5, 7, 9],
    'even': [2, 4, 6, 8]
  }
  */
// Group array of objects by a specific key
const people = [
  { name: "Alice", age: 30 },
  { name: "Bob", age: 25 },
  { name: "Charlie", age: 30 },
];
const groupedByAge = people.groupByKey("age");
console.log(groupedByAge);
/*
  Outputs:
  {
    '25': [ { name: 'Bob', age: 25 } ],
    '30': [ { name: 'Alice', age: 30 }, { name: 'Charlie', age: 30 } ]
  }
  */
// Get distinct elements from an array
const repeatedNumbers = [1, 2, 3, 1, 4, 2, 5];
const distinctNumbers = repeatedNumbers.distinct();
console.log(distinctNumbers); // Outputs: [1, 2, 3, 4, 5]
// Get unique objects based on a specific key
const users = [
  { id: 1, name: "John" },
  { id: 2, name: "Alice" },
  { id: 1, name: "Bob" },
];
const uniqueUsersById = users.uniqueBy("id");
console.log(uniqueUsersById);
/*
  Outputs:
  [
    { id: 1, name: 'John' },
    { id: 2, name: 'Alice' }
  ]
  */
// Sort array based on a custom callback
const words = ["apple", "banana", "grape", "orange"];
const sortedByLength = words.sortBy((word) => word.length);
console.log(sortedByLength); // Outputs: ['grape', 'apple', 'banana', 'orange']
// Sort array of objects based on a specific key
const sortedByAge = people.sortByKey("age");
console.log(sortedByAge);
/*
  Outputs:
  [
    { name: 'Bob', age: 25 },
    { name: 'Alice', age: 30 },
    { name: 'Charlie', age: 30 }
  ]
  */
// Compute sum of array elements based on a custom callback
const sumOfSquares = numbers.sum((num) => num * num);
console.log(sumOfSquares); // Outputs: 285
// Compute sum of array of objects based on a specific key
const totalAge = people.sumByKey("age");
console.log(totalAge); // Outputs: 85
// Split array into chunks of a specified size
const chunkedNumbers = numbers.chunk(3);
console.log(chunkedNumbers);
/*
  Outputs:
  [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
  ]
  */
// Get unique elements from an array
const uniqueElements = repeatedNumbers.unique();
console.log(uniqueElements); // Outputs: [1, 2, 3, 4, 5]
// Remove a specific item from the array
const filteredNumbers = repeatedNumbers.remove(2);
console.log(filteredNumbers); // Outputs: [1, 3, 1, 4, 5]
// Remove items based on a specific key-value pair
const filteredUsers = users.removeByKeyValue("id", 1);
console.log(filteredUsers);
/*
  Outputs:
  [
    { id: 2, name: 'Alice' }
  ]
  */
// Find the index of an object based on a specific key-value pair
const indexOfBob = users.findIndexByKeyValue("name", "Bob");
console.log(indexOfBob); // Outputs: 2
// Find an object based on a specific key-value pair
const alice = users.findByKeyValue("name", "Alice");
console.log(alice); // Outputs: { id: 2, name: 'Alice' }
// Find the value of a specific key in an object based on another key-value pair
const retrieveAge = people.findValueByKeyValue("name", "Alice", "age");
console.log(retrieveAge); // Outputs: 30