feat: frontend unit tests

frontend/tests/utils/helpers/replacementStrings.test.ts

@@ -0,0 +1,68 @@
+import { replaceString } from '../../../src/static/js/utils/helpers/replacementStrings';
+
+declare global {
+    interface Window {
+        REPLACEMENTS?: Record<string, string>;
+    }
+}
+
+describe('js/utils/helpers', () => {
+    describe('replacementStrings', () => {
+        describe('replaceString', () => {
+            const originalReplacements = window.REPLACEMENTS;
+
+            beforeEach(() => {
+                delete window.REPLACEMENTS;
+            });
+
+            afterEach(() => {
+                window.REPLACEMENTS = originalReplacements;
+            });
+
+            test('Returns the original word when window.REPLACEMENTS is undefined', () => {
+                delete window.REPLACEMENTS;
+                const input = 'Hello World';
+                const output = replaceString(input);
+                expect(output).toBe(input);
+            });
+
+            test('Replaces a single occurrence based on window.REPLACEMENTS map', () => {
+                window.REPLACEMENTS = { Hello: 'Hi' };
+                const output = replaceString('Hello World');
+                expect(output).toBe('Hi World');
+            });
+
+            test('Replaces multiple occurrences of the same key', () => {
+                window.REPLACEMENTS = { foo: 'bar' };
+                const output = replaceString('foo foo baz foo');
+                expect(output).toBe('bar bar baz bar');
+            });
+
+            test('Applies all entries in window.REPLACEMENTS (sequential split/join)', () => {
+                window.REPLACEMENTS = { a: 'A', A: 'X' };
+                // First replaces 'a'->'A' and then 'A'->'X'
+                const output = replaceString('aAaa');
+                expect(output).toBe('XXXX');
+            });
+
+            test('Supports empty string replacements (deletion)', () => {
+                window.REPLACEMENTS = { remove: '' };
+                const output = replaceString('please remove this');
+                expect(output).toBe('please  this');
+            });
+
+            test('Handles overlapping keys by iteration order', () => {
+                window.REPLACEMENTS = { ab: 'X', b: 'Y' };
+                // First replaces 'ab' -> 'X', leaving no 'b' from that sequence, then replace standalone 'b' -> 'Y'
+                const output = replaceString('zab+b');
+                expect(output).toBe('zX+Y');
+            });
+
+            test('Works with special regex characters since split/join is literal', () => {
+                window.REPLACEMENTS = { '.': 'DOT', '*': 'STAR', '[]': 'BRACKETS' };
+                const output = replaceString('a.*b[]c.');
+                expect(output).toBe('aDOTSTARbBRACKETScDOT');
+            });
+        });
+    });
+});