first commit

common/resources/client/utils/array/move-multiple-items-in-array.ts

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+export function moveMultipleItemsInArray<T>(
+  array: T[],
+  indexOrIndexes: number | number[],
+  newIndex: number
+) {
+  const indexes = Array.isArray(indexOrIndexes)
+    ? indexOrIndexes
+    : [indexOrIndexes];
+  const insertBefore = array[newIndex + (newIndex < indexes[0] ? 0 : 1)];
+  const itemsToBeMoved = indexes.map(i => array[i]);
+
+  // in original sequence order, check for presence in the removal
+  // list, *and* remove them from the original array
+  const moved = [];
+  for (let i = 0; i < array.length; ) {
+    const value = array[i];
+    if (itemsToBeMoved.indexOf(value) >= 0) {
+      moved.push(value);
+      array.splice(i, 1);
+    } else {
+      ++i;
+    }
+  }
+
+  // find the new index of the insertion point
+  let insertionIndex = array.indexOf(insertBefore);
+  if (insertionIndex < 0) {
+    insertionIndex = array.length;
+  }
+
+  // and add the elements back in
+  array.splice(insertionIndex, 0, ...moved);
+
+  return array;
+}