Array Method Extensions

This package provides a set of useful methods to extend the functionality of the Array class in TypeScript.

Using these methods, you can easily group, map, distinct, merge, and sum arrays. It reduces code complexity and makes
your code more readable.

Index

- Installation
- Usage
- Methods
- distinctBy
- equals
- groupBy
- mapBy
- mergeBy
- sum

Installation

Using Yarn

``sh
yarn add @codura/array-method-extension
`

Using npm

`shell
npm install @codura/array-method-extension
`

Usage

`ts
export * from '@codura/array-method-extension';
`

Methods

$3

Remove duplicates from an Array using a key function

`ts
const usersWithDuplicates = [
{ id: '1', gender: 'male', name: 'John' },
{ id: '2', gender: 'female', name: 'Jane' },
{ id: '1', gender: 'male', name: 'John' },
];
const usersWithoutDuplicates = usersWithDuplicates.distinctBy(user => user.id); // [{ id: '1', gender: 'male', name: 'John' }, { id: '2', gender: 'female', name: 'Jane' }]
`

Remove duplicates from an Array using a key function and a value function

`ts
const usersWithDuplicates = [
{ id: '1', gender: 'male', name: 'John' },
{ id: '2', gender: 'female', name: 'Jane' },
{ id: '1', gender: 'male', name: 'John' },
];
const namesWithoutDuplicates = usersWithDuplicates.distinctBy(user => user.id, user => user.name); // ['John', 'Jane']
`

Check if two arrays, containing decimals, are equal using decimal.js

`ts
import Decimal from 'decimal.js';

const decimals1 = [
new Decimal(23.56457),
new Decimal(12.34543),
new Decimal(34.12345),
];
const decimals2 = [
new Decimal(12.34543),
new Decimal(23.56457),
new Decimal(34.12345),
];
const areEqual = decimals1.equals(decimals2); // true
`

$3

Check if two arrays, containing custom comparable objects, are equal

`ts
class ComparableItem {
constructor(readonly item: string) {
}

equals(comparableItem: ComparableItem) {
return this.item === comparableItem.item;
}
}

const comparableItems1 = [new ComparableItem('a'), new ComparableItem('b')];
const comparableItems2 = [new ComparableItem('b'), new ComparableItem('a')];
const areEqual = comparableItems1.equals(comparableItems2); // true
`

Check if two arrays, containing decimals, are equal using decimal.js

`ts
import Decimal from 'decimal.js';

const decimals1 = [
new Decimal(23.56457),
new Decimal(12.34543),
new Decimal(34.12345),
];
const decimals2 = [
new Decimal(12.34543),
new Decimal(23.56457),
new Decimal(34.12345),
];
const areEqual = decimals1.equals(decimals2); // true
`

$3

Group an Array to a Map using a key function

`ts
const users = [
{ id: '1', gender: 'male', name: 'John' },
{ id: '2', gender: 'female', name: 'Jane' },
{ id: '3', gender: 'male', name: 'Joe' },
];
const usersByGroup = users.groupBy(user => user.gender); // Map([['male', [{id: '1', gender: 'male', name: 'John'}, {id: '3', gender: 'male', name: 'Joe'}]], ['female', [{id: '2', gender: 'female, name: 'Jane'}]]])
`

Group an Array to a map using a key function and a value function

`ts
const users = [
{ id: '1', gender: 'male', name: 'John' },
{ id: '2', gender: 'female', name: 'Jane' },
{ id: '3', gender: 'male', name: 'Joe' },
];
const userNamesById = users.groupBy(user => user.gender, user => user.name); // Map([['male', ['John', 'Joe']], ['female', ['Jane']]])
`

$3

Map an Array to a map using a key function

`ts
const users = [
{ id: '1', name: 'John' },
{ id: '2', name: 'Jane' },
{ id: '3', name: 'Joe' },
];
const usersById = users.mapBy(user => user.id); // Map([['1', {id: '1', gender: 'male', name: 'John'}], ['2', {id: '2', gender: 'female, name: 'Jane'}], ['3', {id: '3', gender: 'male', name: 'Joe'}]])
`

Map an Array to a map using a key function and a value function

`ts
const users = [
{ id: '1', name: 'John' },
{ id: '2', name: 'Jane' },
{ id: '3', name: 'Joe' },
];
const userNamesById = users.mapBy(user => user.id, user => user.name); // Map([['1', 'John'], ['2', 'Jane'], ['3', 'Joe']])
`

$3

Merge custom mergeable objects in an Array

`ts
class Drink {
constructor(readonly name: string, readonly amount: number) {
}

merge(drink: Drink) {
return new Drink(this.name, this.amount + drink.amount);
}
}

const drinks = [
new Drink('beer', 5),
new Drink('wine', 2),
new Drink('beer', 3),
];
const sum = drinks.merge(drink => drink.name); // [Drink('beer', 8), Drink('wine', 2)]
`

$3

Sum custom addable objects in an Array

`ts
class Payment {
constructor(readonly note: string, readonly amount: number) {
}

add(payment: Payment) {
return new Payment(this.note, this.amount + payment.amount);
}
}

const payments = [
new Payment('first', 100),
new Payment('second', 200),
new Payment('third', 300),
];
const sum = payments.sum(new Payment('sum', 0)); // Payment('sum', 600)
`

Sum decimals in an Array using decimal.js

`ts
import Decimal from 'decimal.js';

const decimals = [
new Decimal(23.56457),
new Decimal(12.34543),
new Decimal(34.12345),
];
const sum = payments.sum(new Decimal(0)); // Decimal(70.03345)
``