@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

``bash
npm install @rbxts/default-map
`

Usage

`typescript
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());
listMap.get("fruits").push("apple");
listMap.get("fruits").push("banana");
`

API

$3

`typescript
new DefaultMap(defaultValueCreator: () => V, entries?: ReadonlyArray)
`

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

$3

| 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) => void): void | Iterates over all entries |
| getReadonlyRawMap(): ReadonlyMap | 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