[system-a] utils/refs

src/utils/refs.test.ts

@@ -0,0 +1,12 @@
+import assert from "node:assert"
+import { test } from "node:test"
+import { refs } from "./refs.js"
+
+test("refs", () => {
+  assert.deepStrictEqual(refs([0, 1, 2, 3, 4, 5], [1, 3, 5]), [1, 3, 5])
+  assert.deepStrictEqual(refs([[0], [1], [2], [3], [4], [5]], [1, 3, 5]), [
+    [1],
+    [3],
+    [5],
+  ])
+})

src/utils/refs.ts

@@ -0,0 +1,3 @@
+export function refs<A>(array: Array<A>, indexes: Array<number>): Array<A> {
+  return indexes.map((index) => array[index])
+}