type safe concat

uriva · Aug 23, 2023 · dd56636 · dd56636
1 parent 621165e
commit dd56636
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/src/array.test.ts b/src/array.test.ts
@@ -2,6 +2,7 @@ import {
   all,
   any,
   anymap,
+  concat,
   contains,
   drop,
   enumerate,
@@ -17,6 +18,19 @@ import {
 
 import { assertEquals } from "https://deno.land/std@0.174.0/testing/asserts.ts";
 
+const _: number[] = concat([[1, 2, 3], [0, 0, 0]]);
+
+Deno.test("concat", () => {
+  assertEquals(concat([[1, 2, 3], [0, 0, 0]]), [
+    1,
+    2,
+    3,
+    0,
+    0,
+    0,
+  ]);
+});
+
 Deno.test("zip", () => {
   assertEquals(zip([1, 2, 3], [0, 0, 0]), [
     [1, 0],

diff --git a/src/array.ts b/src/array.ts
@@ -21,7 +21,7 @@ export const unique = <T>(key: (x: T) => Primitive) => (array: T[]) => {
   return result;
 };
 
-export const concat = (array: unknown[][]) => {
+export const concat = <T>(array: T[][]) => {
   const result = [];
   for (const xs of array) {
     for (const x of xs) {