fix: build

packages/collection-utils/test/difference.spec.ts

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2022 StApps
+ *  This program is free software: you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the Free
+ *  Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ *  more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with
+ *  this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+import {differenceBy} from '../src/difference';
+import {expect} from "chai";
+
+describe('differenceBy', function () {
+  it('should return the difference of two arrays', function () {
+    const a = [1, 2, 3, 4, 5];
+    const b = [1, 2, 3];
+
+    expect(differenceBy(a, b, it => it)).to.deep.equal([4, 5]);
+  });
+});