hunk.code_window:   };
   }
   export function indexArray<T, U>(
     list: () => T[],
     mapFn: (v: () => T, i: number) => U,
     options: { fallback?: () => any } = {}
   ): () => U[] {
  
hunk.labels: keep keep keep keep replace keep keep keep
hunk.after_edit:   list: () => readonly T[],
  
hunk.file_path: packages/solid/src/reactive/array.ts
hunk.type: replace
file: import { createRoot, createSignal, createMemo } from "solid-js";
  import { pairwise } from "../src";
  
  describe("Pairwise operator", () => {
    test("simple pairwise", () => {
      createRoot(() => {
        const [s, set] = createSignal("Hi"),
          r = createMemo(pairwise(s));
        expect(r()).toEqual([undefined, "Hi"]);
        set("Lo");
        expect(r()).toEqual(["Hi", "Lo"]);
      });
    });
  
    test("simple pairwise curried", () => {
      createRoot(() => {
        const [s, set] = createSignal("Hi"),
          pair = pairwise(),
          r = createMemo(pair(s));
        expect(r()).toEqual([undefined, "Hi"]);
        set("Lo");
        expect(r()).toEqual(["Hi", "Lo"]);
      });
    });
  });
  