From 94525fce5299f3417801f0152a475892e1edac30 Mon Sep 17 00:00:00 2001
From: "Max P." <Mail@MPassarello.de>
Date: Wed, 7 May 2025 12:28:51 +0200
Subject: [PATCH] test(utils): add unit tests for parseQuery function

- Introduce comprehensive tests for the parseQuery utility.
- Validate handling of single and multi-value query parameters.
- Ensure empty query strings return an empty object.
- Confirm repeated keys are grouped into arrays.

Signed-off-by: Max P. <Mail@MPassarello.de>
---
 src/Utils/__tests__/parseQuery.test.ts | 49 ++++++++++++++++++++++++++
 src/Utils/parseQuery.ts                | 30 ++++++++++++++++
 2 files changed, 79 insertions(+)
 create mode 100644 src/Utils/__tests__/parseQuery.test.ts
 create mode 100644 src/Utils/parseQuery.ts

diff --git a/src/Utils/__tests__/parseQuery.test.ts b/src/Utils/__tests__/parseQuery.test.ts
new file mode 100644
index 0000000..9c4924e
--- /dev/null
+++ b/src/Utils/__tests__/parseQuery.test.ts
@@ -0,0 +1,49 @@
+import { assertEquals } from 'https://deno.land/std/assert/mod.ts';
+import { parseQuery } from '../parseQuery.ts';
+
+Deno.test('parseQuery: single-value parameters are parsed as strings', () => {
+    const url = new URL('http://localhost?foo=bar&limit=10');
+    const result = parseQuery(url.searchParams);
+
+    assertEquals(result, {
+        foo: 'bar',
+        limit: '10',
+    });
+});
+
+Deno.test('parseQuery: multi-value parameters are parsed as string arrays', () => {
+    const url = new URL('http://localhost?tag=ts&tag=deno&tag=web');
+    const result = parseQuery(url.searchParams);
+
+    assertEquals(result, {
+        tag: ['ts', 'deno', 'web'],
+    });
+});
+
+Deno.test('parseQuery: mixed single and multi-value parameters', () => {
+    const url = new URL(
+        'http://localhost?sort=asc&filter=active&filter=pending',
+    );
+    const result = parseQuery(url.searchParams);
+
+    assertEquals(result, {
+        sort: 'asc',
+        filter: ['active', 'pending'],
+    });
+});
+
+Deno.test('parseQuery: empty query string returns empty object', () => {
+    const url = new URL('http://localhost');
+    const result = parseQuery(url.searchParams);
+
+    assertEquals(result, {});
+});
+
+Deno.test('parseQuery: repeated single-value keys are grouped', () => {
+    const url = new URL('http://localhost?a=1&a=2&a=3');
+    const result = parseQuery(url.searchParams);
+
+    assertEquals(result, {
+        a: ['1', '2', '3'],
+    });
+});
diff --git a/src/Utils/parseQuery.ts b/src/Utils/parseQuery.ts
new file mode 100644
index 0000000..5125f52
--- /dev/null
+++ b/src/Utils/parseQuery.ts
@@ -0,0 +1,30 @@
+import { Query } from '../Types/Query.ts';
+
+/**
+ * Parses a `URLSearchParams` object into an `IQuery` structure
+ * that preserves both single and multi-value semantics.
+ *
+ * For each query parameter key, this function checks how often the key appears:
+ * - If the key occurs once, the value is stored as a string.
+ * - If the key occurs multiple times, the values are stored as a string array.
+ *
+ * This ensures compatibility with the `IQuery` type definition,
+ * which allows both `string` and `string[]` as value types.
+ *
+ * Example:
+ *   - ?tag=deno&tag=ts    →  { tag: ["deno", "ts"] }
+ *   - ?page=2             →  { page: "2" }
+ *
+ * @param searchParams - The `URLSearchParams` instance from a parsed URL.
+ * @returns An object conforming to `IQuery`, with normalized parameter values.
+ */
+export function parseQuery(searchParams: URLSearchParams): Query {
+    const query: Query = {};
+
+    for (const key of new Set(searchParams.keys())) {
+        const values = searchParams.getAll(key);
+        query[key] = values.length > 1 ? values : values[0];
+    }
+
+    return query;
+}