Feat(queryToObject): add option to handle arrays

Add option to not overwrite values, but instead
gather them into an array, so we can handle
queries with array values

app/assets/javascripts/lib/utils/url_utility.js

@@ -334,17 +334,32 @@ export function getWebSocketUrl(path) {
  * Convert search query into an object
  *
  * @param {String} query from "document.location.search"
+ * @param {Object} options
+ * @param {Boolean} options.gatherArrays - gather array values into an Array
  * @returns {Object}
  *
  * ex: "?one=1&two=2" into {one: 1, two: 2}
  */
-export function queryToObject(query) {
+export function queryToObject(query, options = {}) {
+  const { gatherArrays = false } = options;
   const removeQuestionMarkFromQuery = String(query).startsWith('?') ? query.slice(1) : query;
   return removeQuestionMarkFromQuery.split('&').reduce((accumulator, curr) => {
     const [key, value] = curr.split('=');
-    if (value !== undefined) {
-      accumulator[decodeURIComponent(key)] = decodeURIComponent(value);
+    if (value === undefined) {
+      return accumulator;
+    }
+    const decodedValue = decodeURIComponent(value);
+
+    if (gatherArrays && key.endsWith('[]')) {
+      const decodedKey = decodeURIComponent(key.slice(0, -2));
+      if (!Array.isArray(accumulator[decodedKey])) {
+        accumulator[decodedKey] = [];
       }
+      accumulator[decodedKey].push(decodedValue);
+    } else {
+      accumulator[decodeURIComponent(key)] = decodedValue;
+    }
+
     return accumulator;
   }, {});
 }

spec/frontend/lib/utils/url_utility_spec.js

@@ -616,6 +616,35 @@ describe('URL utility', () => {
 
       expect(urlUtils.queryToObject(searchQuery)).toEqual({ one: '1', two: '2' });
     });
+
+    describe('with gatherArrays=false', () => {
+      it('overwrites values with the same array-key and does not change the key', () => {
+        const searchQuery = '?one[]=1&one[]=2&two=2&two=3';
+
+        expect(urlUtils.queryToObject(searchQuery)).toEqual({ 'one[]': '2', two: '3' });
+      });
+    });
+
+    describe('with gatherArrays=true', () => {
+      const options = { gatherArrays: true };
+      it('gathers only values with the same array-key and strips `[]` from the key', () => {
+        const searchQuery = '?one[]=1&one[]=2&two=2&two=3';
+
+        expect(urlUtils.queryToObject(searchQuery, options)).toEqual({ one: ['1', '2'], two: '3' });
+      });
+
+      it('overwrites values with the same array-key name', () => {
+        const searchQuery = '?one=1&one[]=2&two=2&two=3';
+
+        expect(urlUtils.queryToObject(searchQuery, options)).toEqual({ one: ['2'], two: '3' });
+      });
+
+      it('overwrites values with the same key name', () => {
+        const searchQuery = '?one[]=1&one=2&two=2&two=3';
+
+        expect(urlUtils.queryToObject(searchQuery, options)).toEqual({ one: '2', two: '3' });
+      });
+    });
   });
 
   describe('objectToQuery', () => {