@cch137/group

The @cch137/group package provides a Group class that extends the functionality of arrays, along with Collection and WeakCollection classes for managing groups of items with added convenience methods. This package works in both the browser and Node.js environments.

Installation

npm install @cch137/group

Usage

Group

The Group class extends the native Array class, providing additional methods for managing items.

Example

import Group from "@cch137/group";

const group = new Group<number>();

// Add items to the group
group.add(1, 2, 3);
console.log(group); // Output: [1, 2, 3]

// Check if an item exists
console.log(group.has(2)); // Output: true
console.log(group.has(4)); // Output: false

// Delete an item
group.delete(2);
console.log(group); // Output: [1, 3]

// Delete the last occurrence of an item
group.add(3, 3, 3);
group.deleteLast(3);
console.log(group); // Output: [1, 3, 3]

// Delete one occurrence of an item
group.deleteOne(3);
console.log(group); // Output: [1, 3]

// Clear the group
group.clear();
console.log(group); // Output: []

Collection

The Collection class extends Map and provides methods for managing groups of items associated with keys.

Example

import { Collection } from "@cch137/group";

const collection = new Collection<string, number>();

// Add items to a group in the collection
collection.group("group1").add(1, 2, 3);
console.log(collection.get("group1")); // Output: [1, 2, 3]

// Retrieve and delete a group
const group1 = collection.once("group1");
console.log(group1); // Output: [1, 2, 3]
console.log(collection.get("group1")); // Output: undefined

// Add items and trim empty groups
collection.group("group2").add(4, 5);
collection.group("group2").delete(4);
collection.trim();
console.log(collection.get("group2")); // Output: [5]

WeakCollection

The WeakCollection class extends WeakMap and provides similar functionality to Collection, but for weakly-referenced keys.

Example

import { WeakCollection } from "@cch137/group";

const weakCollection = new WeakCollection<object, number>();
const key = {};

weakCollection.group(key).add(1, 2, 3);
console.log(weakCollection.get(key)); // Output: [1, 2, 3]

const weakGroup = weakCollection.once(key);
console.log(weakGroup); // Output: [1, 2, 3]
console.log(weakCollection.get(key)); // Output: undefined