adds bubble sort

ts/bubble_sort.test.ts

@@ -0,0 +1,18 @@
+function bubble_sort(arr: number[]): void {
+    for (let i = 0; i < arr.length; i++) {
+        for (let j = 0; j < arr.length - 1; j++) {
+            if (arr[j] > arr[j + 1]) {
+                const t = arr[j+1];
+                arr[j+1] = arr[j];
+                arr[j] = t;
+
+            }
+        }
+    }
+}
+
+test("bubble sort works", () => {
+    const a = [2, 1, 3, 4, 5];
+    bubble_sort(a);
+    expect(a).toEqual([1, 2, 3, 4, 5]);
+})