@rbxts/default-map

A roblox-ts Map wrapper that automatically creates default values for missing keys.

Features

• Automatic default values: When accessing a non-existent key, a default value is created and stored
• Type-safe: Full TypeScript generics support for keys and values
• Standard Map API: Implements familiar Map methods like get, set, delete, clear, forEach
• Always returns a value: The has() method always returns true since any key can be accessed

Installation

npm install @rbxts/default-map

Usage

import { DefaultMap } from "@rbxts/default-map";

// Create a DefaultMap with a default value creator
const counterMap = new DefaultMap(() => 0);

// Accessing a non-existent key creates and returns the default value
counterMap.get("apples"); // Returns 0, creates entry for "apples"

// Increment the counter
counterMap.set("apples", counterMap.get("apples") + 1);
counterMap.get("apples"); // Returns 1

// Works with complex default values
const listMap = new DefaultMap(() => new Array<string>());
listMap.get("fruits").push("apple");
listMap.get("fruits").push("banana");

API

Constructor

new DefaultMap<K, V>(defaultValueCreator: () => V, entries?: ReadonlyArray<readonly [K, V]>)

• defaultValueCreator: Function that creates a new default value when needed
• entries: Optional initial key-value pairs

Methods

| Method | Description | |--------|-------------| | get(key: K): V | Returns the value for key, creating a default if missing | | set(key: K, value: V): this | Sets the value for key | | delete(key: K): boolean | Removes the entry for key | | clear(): void | Removes all entries | | has(key: K): boolean | Always returns true | | size(): number | Returns the number of entries | | isEmpty(): boolean | Returns true if the map has no entries | | forEach(callbackfn: (value: V, key: K, map: Map<K, V>) => void): void | Iterates over all entries | | getReadonlyRawMap(): ReadonlyMap<K, V> | Returns the underlying Map |

Dependencies

This package has no external dependencies. It only uses the built-in Map type from TypeScript/roblox-ts.

License

MIT