Fix get type to include undefined and add documentation

lib/index.d.ts

@@ -56,24 +56,112 @@ export type EntityType<T> = T extends Entity<infer A> ? A : never;
 export type InferComponents<A extends Entity[]> = {
     [K in keyof A]: EntityType<A[K]>
 };
-
+type PossiblyUndefinedPack<T extends unknown[]> = {
+	[K in keyof T]: T[K] | undefined
+}
 
 export class World {
+
+	/**
+	 * Creates a new World
+	 */
+	constructor();
+
+	/**
+	 * Creates a new entity
+	 * @returns Entity
+	 */
     entity(): Entity;
+
+	/**
+	 * Creates a new entity located in the first 256 ids.
+	 * These should be used for static components for fast access.
+	 * @returns Entity<T>
+	 */
     component<T = unknown>(): Entity<T>;
 
+	/**
+	 * Gets the target of a relationship. For example, when a user calls
+	 * `world.target(id, ChildOf(parent))`, you will obtain the parent entity.
+	 * @param id Entity
+	 * @param relation The Relationship
+	 * @returns The Parent Entity if it exists
+	 */
     target(id: Entity, relation: Entity): Entity | undefined;
+
+	/**
+	 * Deletes an entity and all its related components and relationships.
+	 * @param id Entity to be destroyed
+	 */
     delete(id: Entity): void;
 
+	/**
+	 * Adds a component to the entity with no value
+	 * @param id Target Entity
+	 * @param component Component
+	 */
     add<T>(id: Entity, component: Entity<T>): void;
+
+	/**
+	 * Assigns a value to a component on the given entity
+	 * @param id Target Entity
+	 * @param component Target Component
+	 * @param data Component Data
+	 */
     set<T>(id: Entity, component: Entity<T>, data: T): void;
+
+	/**
+	 * Removes a component from the given entity
+	 * @param id Target Entity
+	 * @param component Target Component
+	 */
     remove(id: Entity, component: Entity): void;
 
-    get<A>(id: number, component: Entity<A>): A; // Manually typed out since there is a hard limit.
+	// Manually typed out get since there is a hard limit.
-    get<A, B>(id: number, component: Entity<A>, component2: Entity<B>): LuaTuple<[A, B]>;
+
-    get<A, B, C>(id: number, component: Entity<A>, component2: Entity<B>, component3: Entity<C>): LuaTuple<[A, B, C]>;
+	/**
-    get<A, B, C, D>(id: number, component: Entity<A>, component2: Entity<B>, component3: Entity<C>, component4: Entity<D>): LuaTuple<[A, B, C, D]>;
+	 * Retrieves the value of one component. This value may be undefined.
+	 * @param id Target Entity
+	 * @param component Target Component
+	 * @returns Data associated with the component if it exists
+	 */
+    get<A>(id: number, component: Entity<A>): A | undefined;
+
+	/**
+	 * Retrieves the value of two components. This value may be undefined.
+	 * @param id Target Entity
+	 * @param component Target Component 1
+	 * @param component2 Target Component 2
+	 * @returns Data associated with the components if it exists
+	 */
+    get<A, B>(id: number, component: Entity<A>, component2: Entity<B>): LuaTuple<PossiblyUndefinedPack<[A, B]>>;
+
+	/**
+	 * Retrieves the value of three components. This value may be undefined.
+	 * @param id Target Entity
+	 * @param component Target Component 1
+	 * @param component2 Target Component 2
+	 * @param component3 Target Component 3
+	 * @returns Data associated with the components if it exists
+	 */
+    get<A, B, C>(id: number, component: Entity<A>, component2: Entity<B>, component3: Entity<C>): LuaTuple<PossiblyUndefinedPack<[A, B, C]>>;
+
+	/**
+	 * Retrieves the value of four components. This value may be undefined.
+	 * @param id Target Entity
+	 * @param component Target Component 1
+	 * @param component2 Target Component 2
+	 * @param component3 Target Component 3
+	 * @param component4 Target Component 4
+	 * @returns Data associated with the components if it exists
+	 */
+    get<A, B, C, D>(id: number, component: Entity<A>, component2: Entity<B>, component3: Entity<C>, component4: Entity<D>): LuaTuple<PossiblyUndefinedPack<[A, B, C, D]>>;
     
+	/**
+	 * Searches the world for entities that match a given query
+	 * @param components Queried Components
+	 * @returns Iterable function
+	 */
     query<T extends Entity[]>(...components: T): Query<InferComponents<T>>
 }