Class Set

src/lualib/Set.ts:1–252

export class Set<T extends AnyNotNil> {
    public static [Symbol.species] = Set;
    public [Symbol.toStringTag] = "Set";

    public size = 0;

    private firstKey: T | undefined;
    private lastKey: T | undefined;
    private nextKey = new LuaTable<T, T>();
    private previousKey = new LuaTable<T, T>();

    constructor(values?: Iterable<T> | T[]) {
        if (values === undefined) return;

        const iterable = values as Iterable<T>;
        if (iterable[Symbol.iterator]) {
            // Iterate manually because Set is compiled with ES5 which doesn't support Iterables in for...of
            const iterator = iterable[Symbol.iterator]();
            while (true) {
                const result = iterator.next();
                if (result.done) {
                    break;
                }
                this.add(result.value);
            }
        } else {
            const array = values as T[];
            for (const value of array) {
                this.add(value);
            }
        }
    }

    public add(value: T): Set<T> {
        const isNewValue = !this.has(value);
        if (isNewValue) {
            this.size++;
        }

        // Do order bookkeeping
        if (this.firstKey === undefined) {
            this.firstKey = value;
            this.lastKey = value;
        } else if (isNewValue) {
            this.nextKey.set(this.lastKey!, value);
            this.previousKey.set(value, this.lastKey!);
            this.lastKey = value;
        }

        return this;
    }

    public clear(): void {
        this.nextKey = new LuaTable();
        this.previousKey = new LuaTable();
        this.firstKey = undefined;
        this.lastKey = undefined;
        this.size = 0;
    }