Merge branch 'master' into ts_unit

* master:
  Move `./srcts` configs to top level to support types installation from GitHub (#3425)
  insertTab() now handles position correctly when target is NULL (#3404)
  yarn add node-gyp; yarn build (#3424)
  Export TypeScript type definitions to local folder (#3418)
  TypeScript: Remove `any` types / improve type definitions (#3414)
  Better color constrasting in sliderInput() (#3366)
  Use ggplot2::get_alt_text() if available to provide better default alt text (#3398)
  Set selectize dropdownParent to "body" to prevent clipping

srcts/src/utils/__tests__/utils.test.ts

@@ -1,5 +1,33 @@
-import { asArray } from "../";
+import { asArray, mergeSort } from "../";
 
 test("integer is converted to integer array", () => {
   expect(asArray(4)).toStrictEqual([4]);
 });
+
+test("mergeSort merges two arrays", () => {
+  function shuffleArray<T>(arr: Array<T>): Array<T> {
+    if (arr.length < 2) return arr;
+
+    const copy = [...arr];
+
+    copy.sort(() => Math.random() - 0.5);
+    for (let i = 0; i < copy.length; i++) {
+      // if at least one entry is different, return it
+      if (arr[i] !== copy[i]) {
+        return copy;
+      }
+    }
+    // Try shuffling again (rare)
+    return shuffleArray(arr);
+  }
+
+  const original = [1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5];
+  const input = shuffleArray(original);
+
+  const output = mergeSort(input, function (x, y) {
+    return x - y;
+  });
+
+  expect(original).not.toEqual(input);
+  expect(original).toEqual(output);
+});