Fix type errors

Signed-off-by: Sebastian Malton <sebastian@malton.name>

packages/utility-features/utilities/src/iter.ts

@@ -11,6 +11,8 @@ interface Iterator<T> extends Iterable<T> {
   find(fn: (val: T) => unknown): T | undefined;
   collect<U>(fn: (values: Iterable<T>) => U): U;
   toArray(): T[];
+  toMap(): T extends [infer K, infer V] ? Map<K, V> : never;
+  toSet(): Set<T>;
   map<U>(fn: (val: T) => U): Iterator<U>;
   flatMap<U>(fn: (val: T) => U[]): Iterator<U>;
   concat(src2: IterableIterator<T>): Iterator<T>;
@@ -28,6 +30,8 @@ function chain<T>(src: IterableIterator<T>): Iterator<T> {
     join: (sep) => join(src, sep),
     collect: (fn) => fn(src),
     toArray: () => [...src],
+    toMap: () => new Map(src as IterableIterator<[any, any]>) as any,
+    toSet: () => new Set(src),
     concat: (src2) => chain(concat(src, src2)),
     take: (count) => chain(take(src, count)),
     [Symbol.iterator]: () => src,