Array index

1 files changed, 6 insertions, 0 deletions

diff --git a/src/ffi.js b/src/ffi.js
index 81362bb..c0b2076 100644
--- a/src/ffi.js
+++ b/src/ffi.js
@@ -1,3 +1,5 @@
+import { Ok, Error } from "./gleam.js";
+
 export function toArray(list) {
   return list.toArray();
 }
@@ -17,3 +19,7 @@ export function reduce(thing, acc, fn) {
 export function reduceRight(thing, acc, fn) {
   return thing.reduceRight(fn, acc);
 }
+
+export function index(thing, index) {
+  return index in thing ? new Ok(thing[index]) : new Error(undefined);
+}