From 35c2b91534e47fd17b254f1bdfa016d22f21a820 Mon Sep 17 00:00:00 2001
From: Faisal Salman <f@faisalman.com>
Date: Fri, 14 Apr 2023 15:36:37 +0700
Subject: [PATCH] Fix: accept empty string as input

---
 src/ua-parser.js                      | 23 ++++++++++-------------
 test/playwright-test-browser.spec.mjs | 12 ++++++++++++
 2 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/src/ua-parser.js b/src/ua-parser.js
index d72fda7..5f30625 100755
--- a/src/ua-parser.js
+++ b/src/ua-parser.js
@@ -918,10 +918,10 @@
     // Constructor
     ////////////////
 
-    function UACHData (uach, isHTTP_UACH) {
+    function UACHData (uach, isHttpUACH) {
         uach = uach || {};
         setProps.call(this, CH_ALL_VALUES);
-        if (isHTTP_UACH) {
+        if (isHttpUACH) {
             setProps.call(this, [
                 [BRANDS, itemListToArray(uach[CH_HEADER])],
                 [FULLVERLIST, itemListToArray(uach[CH_HEADER_FULL_VER_LIST])],
@@ -1106,15 +1106,12 @@
             return new UAParser(ua, extensions, headers).getResult();
         }
 
-        var userAgent = ua || 
-                        ((NAVIGATOR && NAVIGATOR.userAgent) ? 
-                            NAVIGATOR.userAgent : 
-                            (headers && headers[USER_AGENT] ? 
-                                headers[USER_AGENT] : 
-                                EMPTY)),
-            
-            HTTP_UACH = new UACHData(headers, true),
+        var userAgent = typeof ua === STR_TYPE ? ua :                                       // Passed user-agent string
+                            ((NAVIGATOR && NAVIGATOR.userAgent) ? NAVIGATOR.userAgent :     // navigator.userAgent
+                                (headers && headers[USER_AGENT] ? headers[USER_AGENT] :     // User-Agent from passed headers
+                                    EMPTY)),                                                // empty string
 
+            httpUACH = new UACHData(headers, true),
             regexMap = extensions ? 
                         extend(defaultRegexes, extensions) : 
                         defaultRegexes,
@@ -1122,7 +1119,7 @@
             createItemFunc = function (itemType) {
                 if (itemType == UA_RESULT) {
                     return function () {
-                        return new UAItem(itemType, userAgent, regexMap, HTTP_UACH)
+                        return new UAItem(itemType, userAgent, regexMap, httpUACH)
                                     .set('ua', userAgent)
                                     .set(UA_BROWSER, this.getBrowser())
                                     .set(UA_CPU, this.getCPU())
@@ -1133,13 +1130,13 @@
                     };
                 } else {
                     return function () {
-                        return new UAItem(itemType, userAgent, regexMap[itemType], HTTP_UACH)
+                        return new UAItem(itemType, userAgent, regexMap[itemType], httpUACH)
                                     .parseUA()
                                     .get();
                     };
                 }
             };
-
+            
         // public methods
         setProps.call(this, [
             ['getBrowser', createItemFunc(UA_BROWSER)],
diff --git a/test/playwright-test-browser.spec.mjs b/test/playwright-test-browser.spec.mjs
index a3fb5b8..bab1f3a 100644
--- a/test/playwright-test-browser.spec.mjs
+++ b/test/playwright-test-browser.spec.mjs
@@ -5,6 +5,18 @@ import url from 'url';
 
 const localHtml = `file://${path.resolve(path.dirname(url.fileURLToPath(import.meta.url)), '../')}/dist/ua-parser.html`;
 
+test.describe('test input', () => {
+    test.beforeEach(async ({ page }) => {
+        await page.goto(localHtml);
+    });
+
+    test('accept empty string', async ({ page }) => {
+        // @ts-ignore
+        const uap = await page.evaluate(async () => await UAParser(''));
+        expect(uap).toHaveProperty('ua', '');
+    });
+});
+
 test('read client hints data', async ({ page }) => {
     await page.addInitScript(() => {
         Object.defineProperty(navigator, 'userAgentData', {