From d084e3f405c467c3a4e83502df0798d4a336355a Mon Sep 17 00:00:00 2001
From: Paul D'Ambra <paul@posthog.com>
Date: Fri, 27 Oct 2023 13:43:53 +0100
Subject: [PATCH] ok, fix this now

---
 src/__tests__/request-utils.test.ts | 33 ++++++++++++++++++++++++++++-
 src/utils/request-utils.ts          | 18 +++++++++-------
 2 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/src/__tests__/request-utils.test.ts b/src/__tests__/request-utils.test.ts
index 5c9e487ee..9472e4e91 100644
--- a/src/__tests__/request-utils.test.ts
+++ b/src/__tests__/request-utils.test.ts
@@ -1,4 +1,4 @@
-import { _HTTPBuildQuery, _isUrlMatchingRegex } from '../utils/request-utils'
+import { _getQueryParam, _HTTPBuildQuery, _isUrlMatchingRegex } from '../utils/request-utils'
 
 describe('request utils', () => {
     describe('_HTTPBuildQuery', () => {
@@ -10,6 +10,37 @@ describe('request utils', () => {
             expect(_HTTPBuildQuery(formData)).toEqual(expected)
         })
     })
+
+    describe('_getQueryParam', () => {
+        test.each([
+            ['gets query param', '?name=something', 'name', 'something'],
+            [
+                'gets first query param when multiple matches',
+                '?name=something&name=another&name=third',
+                'name',
+                'something',
+            ],
+            ['gets query param where there is no key in the URL', '?=something', 'name', ''],
+            ['gets query param where there is no value in the URL', '?name=', 'name', ''],
+            ['gets query param where there is no value or = in the URL', '?name', 'name', ''],
+            ['ignores params after the hash', '?name=something#hash?invalid=here', 'invalid', ''],
+            ['ignores params after the hash even with no valid query params', '#hash?invalid=here', 'invalid', ''],
+            ['decodes query param spaces', '?name=something%20encoded', 'name', 'something encoded'],
+            ['decodes query param ampersand', '?name=something%26encoded', 'name', 'something&encoded'],
+            ['decodes query param with +', '?name=something+encoded', 'name', 'something encoded'],
+            ['ignores invalid encoding', '?name=something%2Gencoded', 'name', 'something%2Gencoded'],
+            ['gets query param with trailing slash', '/?name=something', 'name', 'something'],
+            ['gets first query param with multiple params', '/?name=something&test=123', 'name', 'something'],
+            ['gets second query param with multiple params', '/?name=something&test=123', 'test', '123'],
+            ['gets param when no match', '', 'name', ''],
+            ['gets param when no match with trailing slash', '/', 'name', ''],
+            ['gets param when no match and there are params', '/?test=123', 'name', ''],
+            ['gets param when no match and there are params with trailing slash', '/?test=123', 'name', ''],
+        ])('%s', (_name, url, param, expected) => {
+            expect(_getQueryParam(`https://example.com${url}`, param)).toEqual(expected)
+        })
+    })
+
     describe('_isUrlMatchingRegex', () => {
         test.each([
             ['match query params', 'https://example.com?name=something', '(\\?|\\&)(name.*)\\=([^&]+)', true],
diff --git a/src/utils/request-utils.ts b/src/utils/request-utils.ts
index a140fbcad..0c64475ef 100644
--- a/src/utils/request-utils.ts
+++ b/src/utils/request-utils.ts
@@ -1,6 +1,6 @@
 import { _each, _isValidRegex, logger } from './'
 
-import { _isNull, _isString, _isUndefined } from './type-utils'
+import { _isArray, _isUndefined } from './type-utils'
 
 const localDomains = ['localhost', '127.0.0.1']
 
@@ -29,13 +29,15 @@ export const _HTTPBuildQuery = function (formdata: Record<string, any>, arg_sepa
 }
 
 export const _getQueryParam = function (url: string, param: string): string {
-    // Expects a raw URL
-
-    const cleanParam = param.replace(/[[]/, '\\[').replace(/[\]]/, '\\]')
-    const regexS = '[\\?&]' + cleanParam + '=([^&#]*)'
-    const regex = new RegExp(regexS)
-    const results = regex.exec(url)
-    if (_isNull(results) || (results && !_isString(results[1]) && (results[1] as any).length)) {
+    const withoutHash: string = url.split('#')[0] || ''
+    const queryParams: string = withoutHash.split('?')[1] || ''
+    const results =
+        queryParams
+            .split('&')
+            .map((part) => part.split('='))
+            .find(([key]) => key === param) || []
+
+    if (!_isArray(results) || results.length < 2) {
         return ''
     } else {
         let result = results[1]