feat: prefer trusted data, fix external deps edge-cases

src/_helpers.ts

@@ -94,3 +94,26 @@ export function versionCompare (a: Version, b: Version): CompareResult {
   return 0
 }
 // endregion version compare
+
+export function * iteratorMap <I, R> (iter: Iterable<I>, func: (e: I) => R): Generator<R> {
+  for (const item of iter) {
+    yield func(item)
+  }
+}
+
+export function * iteratorFilter <I> (iter: Iterable<I>, func: (e: I) => boolean): Generator<I> {
+  for (const item of iter) {
+    if (func(item)) {
+      yield item
+    }
+  }
+}
+
+/* eslint-disable @typescript-eslint/no-unsafe-return, @typescript-eslint/no-unsafe-call
+-- ack */
+/* @ts-expect-error TS2550 -- Set.difference() exists in node since node2024 */
+export const setDifference: <I>(s1: Set<I>, s2: Set<any>) => Set<I> = typeof Set.prototype.difference === 'function'
+  /* @ts-expect-error TS2550 */
+  ? (s1, s2) => s1.difference(s2)
+  : (s1, s2) => new Set(iteratorFilter(s1, (i) => !s2.has(i)) )
+/* eslint-enable @typescript-eslint/no-unsafe-return, @typescript-eslint/no-unsafe-call */