diff --git a/test/helper.py b/test/helper.py
index 0b90660ff..539b2f618 100644
--- a/test/helper.py
+++ b/test/helper.py
@@ -194,8 +194,8 @@ def sanitize_got_info_dict(got_dict):
         'formats', 'thumbnails', 'subtitles', 'automatic_captions', 'comments', 'entries',
 
         # Auto-generated
-        'autonumber', 'playlist', 'format_index', 'video_ext', 'audio_ext', 'duration_string', 'epoch',
-        'fulltitle', 'extractor', 'extractor_key', 'filepath', 'infojson_filename', 'original_url', 'n_entries',
+        'autonumber', 'playlist', 'format_index', 'video_ext', 'audio_ext', 'duration_string', 'epoch', 'n_entries',
+        'fulltitle', 'extractor', 'extractor_key', 'filename', 'filepath', 'infojson_filename', 'original_url',
 
         # Only live_status needs to be checked
         'is_live', 'was_live',
diff --git a/test/test_YoutubeDL.py b/test/test_YoutubeDL.py
index 3c26bd7c6..477fd220e 100644
--- a/test/test_YoutubeDL.py
+++ b/test/test_YoutubeDL.py
@@ -757,7 +757,7 @@ class TestYoutubeDL(unittest.TestCase):
         test('%(id)r %(height)r', "'1234' 1080")
         test('%(ext)s-%(ext|def)d', 'mp4-def')
         test('%(width|0)04d', '0000')
-        test('a%(width|)d', 'a', outtmpl_na_placeholder='none')
+        test('a%(width|b)d', 'ab', outtmpl_na_placeholder='none')
 
         FORMATS = self.outtmpl_info['formats']
         sanitize = lambda x: x.replace(':', '：').replace('"', "＂").replace('\n', ' ')
@@ -871,12 +871,12 @@ class TestYoutubeDL(unittest.TestCase):
 
         class SimplePP(PostProcessor):
             def run(self, info):
-                with open(audiofile, 'wt') as f:
+                with open(audiofile, 'w') as f:
                     f.write('EXAMPLE')
                 return [info['filepath']], info
 
         def run_pp(params, PP):
-            with open(filename, 'wt') as f:
+            with open(filename, 'w') as f:
                 f.write('EXAMPLE')
             ydl = YoutubeDL(params)
             ydl.add_post_processor(PP())
@@ -895,7 +895,7 @@ class TestYoutubeDL(unittest.TestCase):
 
         class ModifierPP(PostProcessor):
             def run(self, info):
-                with open(info['filepath'], 'wt') as f:
+                with open(info['filepath'], 'w') as f:
                     f.write('MODIFIED')
                 return [], info
 
diff --git a/test/test_jsinterp.py b/test/test_jsinterp.py
index 26711502a..444909b84 100644
--- a/test/test_jsinterp.py
+++ b/test/test_jsinterp.py
@@ -14,462 +14,302 @@ from yt_dlp.jsinterp import JS_Undefined, JSInterpreter
 
 
 class TestJSInterpreter(unittest.TestCase):
-    def test_basic(self):
-        jsi = JSInterpreter('function x(){;}')
-        self.assertEqual(jsi.call_function('x'), None)
-
-        jsi = JSInterpreter('function x3(){return 42;}')
-        self.assertEqual(jsi.call_function('x3'), 42)
+    def _test(self, code, ret, func='f', args=()):
+        self.assertEqual(JSInterpreter(code).call_function(func, *args), ret)
 
-        jsi = JSInterpreter('function x3(){42}')
-        self.assertEqual(jsi.call_function('x3'), None)
+    def test_basic(self):
+        jsi = JSInterpreter('function f(){;}')
+        self.assertEqual(repr(jsi.extract_function('f')), 'F<f>')
+        self.assertEqual(jsi.call_function('f'), None)
 
-        jsi = JSInterpreter('var x5 = function(){return 42;}')
-        self.assertEqual(jsi.call_function('x5'), 42)
+        self._test('function f(){return 42;}', 42)
+        self._test('function f(){42}', None)
+        self._test('var f = function(){return 42;}', 42)
 
     def test_calc(self):
-        jsi = JSInterpreter('function x4(a){return 2*a+1;}')
-        self.assertEqual(jsi.call_function('x4', 3), 7)
+        self._test('function f(a){return 2*a+1;}', 7, args=[3])
 
     def test_empty_return(self):
-        jsi = JSInterpreter('function f(){return; y()}')
-        self.assertEqual(jsi.call_function('f'), None)
+        self._test('function f(){return; y()}', None)
 
     def test_morespace(self):
-        jsi = JSInterpreter('function x (a) { return 2 * a + 1 ; }')
-        self.assertEqual(jsi.call_function('x', 3), 7)
-
-        jsi = JSInterpreter('function f () { x =  2  ; return x; }')
-        self.assertEqual(jsi.call_function('f'), 2)
+        self._test('function f (a) { return 2 * a + 1 ; }', 7, args=[3])
+        self._test('function f () { x =  2  ; return x; }', 2)
 
     def test_strange_chars(self):
-        jsi = JSInterpreter('function $_xY1 ($_axY1) { var $_axY2 = $_axY1 + 1; return $_axY2; }')
-        self.assertEqual(jsi.call_function('$_xY1', 20), 21)
+        self._test('function $_xY1 ($_axY1) { var $_axY2 = $_axY1 + 1; return $_axY2; }',
+                   21, args=[20], func='$_xY1')
 
     def test_operators(self):
-        jsi = JSInterpreter('function f(){return 1 << 5;}')
-        self.assertEqual(jsi.call_function('f'), 32)
-
-        jsi = JSInterpreter('function f(){return 2 ** 5}')
-        self.assertEqual(jsi.call_function('f'), 32)
-
-        jsi = JSInterpreter('function f(){return 19 & 21;}')
-        self.assertEqual(jsi.call_function('f'), 17)
-
-        jsi = JSInterpreter('function f(){return 11 >> 2;}')
-        self.assertEqual(jsi.call_function('f'), 2)
-
-        jsi = JSInterpreter('function f(){return []? 2+3: 4;}')
-        self.assertEqual(jsi.call_function('f'), 5)
-
-        jsi = JSInterpreter('function f(){return 1 == 2}')
-        self.assertEqual(jsi.call_function('f'), False)
-
-        jsi = JSInterpreter('function f(){return 0 && 1 || 2;}')
-        self.assertEqual(jsi.call_function('f'), 2)
-
-        jsi = JSInterpreter('function f(){return 0 ?? 42;}')
-        self.assertEqual(jsi.call_function('f'), 0)
-
-        jsi = JSInterpreter('function f(){return "life, the universe and everything" < 42;}')
-        self.assertFalse(jsi.call_function('f'))
+        self._test('function f(){return 1 << 5;}', 32)
+        self._test('function f(){return 2 ** 5}', 32)
+        self._test('function f(){return 19 & 21;}', 17)
+        self._test('function f(){return 11 >> 2;}', 2)
+        self._test('function f(){return []? 2+3: 4;}', 5)
+        self._test('function f(){return 1 == 2}', False)
+        self._test('function f(){return 0 && 1 || 2;}', 2)
+        self._test('function f(){return 0 ?? 42;}', 0)
+        self._test('function f(){return "life, the universe and everything" < 42;}', False)
 
     def test_array_access(self):
-        jsi = JSInterpreter('function f(){var x = [1,2,3]; x[0] = 4; x[0] = 5; x[2.0] = 7; return x;}')
-        self.assertEqual(jsi.call_function('f'), [5, 2, 7])
+        self._test('function f(){var x = [1,2,3]; x[0] = 4; x[0] = 5; x[2.0] = 7; return x;}', [5, 2, 7])
 
     def test_parens(self):
-        jsi = JSInterpreter('function f(){return (1) + (2) * ((( (( (((((3)))))) )) ));}')
-        self.assertEqual(jsi.call_function('f'), 7)
-
-        jsi = JSInterpreter('function f(){return (1 + 2) * 3;}')
-        self.assertEqual(jsi.call_function('f'), 9)
+        self._test('function f(){return (1) + (2) * ((( (( (((((3)))))) )) ));}', 7)
+        self._test('function f(){return (1 + 2) * 3;}', 9)
 
     def test_quotes(self):
-        jsi = JSInterpreter(R'function f(){return "a\"\\("}')
-        self.assertEqual(jsi.call_function('f'), R'a"\(')
+        self._test(R'function f(){return "a\"\\("}', R'a"\(')
 
     def test_assignments(self):
-        jsi = JSInterpreter('function f(){var x = 20; x = 30 + 1; return x;}')
-        self.assertEqual(jsi.call_function('f'), 31)
-
-        jsi = JSInterpreter('function f(){var x = 20; x += 30 + 1; return x;}')
-        self.assertEqual(jsi.call_function('f'), 51)
-
-        jsi = JSInterpreter('function f(){var x = 20; x -= 30 + 1; return x;}')
-        self.assertEqual(jsi.call_function('f'), -11)
+        self._test('function f(){var x = 20; x = 30 + 1; return x;}', 31)
+        self._test('function f(){var x = 20; x += 30 + 1; return x;}', 51)
+        self._test('function f(){var x = 20; x -= 30 + 1; return x;}', -11)
 
     def test_comments(self):
         'Skipping: Not yet fully implemented'
         return
-        jsi = JSInterpreter('''
-        function x() {
-            var x = /* 1 + */ 2;
-            var y = /* 30
-            * 40 */ 50;
-            return x + y;
-        }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 52)
-
-        jsi = JSInterpreter('''
-        function f() {
-            var x = "/*";
-            var y = 1 /* comment */ + 2;
-            return y;
-        }
-        ''')
-        self.assertEqual(jsi.call_function('f'), 3)
+        self._test('''
+            function f() {
+                var x = /* 1 + */ 2;
+                var y = /* 30
+                * 40 */ 50;
+                return x + y;
+            }
+        ''', 52)
+
+        self._test('''
+            function f() {
+                var x = "/*";
+                var y = 1 /* comment */ + 2;
+                return y;
+            }
+        ''', 3)
 
     def test_precedence(self):
-        jsi = JSInterpreter('''
-        function x() {
-            var a = [10, 20, 30, 40, 50];
-            var b = 6;
-            a[0]=a[b%a.length];
-            return a;
-        }''')
-        self.assertEqual(jsi.call_function('x'), [20, 20, 30, 40, 50])
+        self._test('''
+            function f() {
+                var a = [10, 20, 30, 40, 50];
+                var b = 6;
+                a[0]=a[b%a.length];
+                return a;
+            }
+        ''', [20, 20, 30, 40, 50])
 
     def test_builtins(self):
-        jsi = JSInterpreter('''
-        function x() { return NaN }
-        ''')
-        self.assertTrue(math.isnan(jsi.call_function('x')))
+        jsi = JSInterpreter('function f() { return NaN }')
+        self.assertTrue(math.isnan(jsi.call_function('f')))
 
-        jsi = JSInterpreter('''
-        function x() { return new Date('Wednesday 31 December 1969 18:01:26 MDT') - 0; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 86000)
-        jsi = JSInterpreter('''
-        function x(dt) { return new Date(dt) - 0; }
-        ''')
-        self.assertEqual(jsi.call_function('x', 'Wednesday 31 December 1969 18:01:26 MDT'), 86000)
+        self._test('function f() { return new Date("Wednesday 31 December 1969 18:01:26 MDT") - 0; }',
+                   86000)
+        self._test('function f(dt) { return new Date(dt) - 0; }',
+                   86000, args=['Wednesday 31 December 1969 18:01:26 MDT'])
 
     def test_call(self):
         jsi = JSInterpreter('''
-        function x() { return 2; }
-        function y(a) { return x() + (a?a:0); }
-        function z() { return y(3); }
+            function x() { return 2; }
+            function y(a) { return x() + (a?a:0); }
+            function z() { return y(3); }
         ''')
         self.assertEqual(jsi.call_function('z'), 5)
         self.assertEqual(jsi.call_function('y'), 2)
 
     def test_if(self):
-        jsi = JSInterpreter('''
-        function x() {
-            let a = 9;
-            if (0==0) {a++}
-            return a
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
-
-        jsi = JSInterpreter('''
-        function x() {
-            if (0==0) {return 10}
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
-
-        jsi = JSInterpreter('''
-        function x() {
-            if (0!=0) {return 1}
-            else {return 10}
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
+        self._test('''
+            function f() {
+                let a = 9;
+                if (0==0) {a++}
+                return a
+            }
+        ''', 10)
+
+        self._test('''
+            function f() {
+                if (0==0) {return 10}
+            }
+        ''', 10)
+
+        self._test('''
+            function f() {
+                if (0!=0) {return 1}
+                else {return 10}
+            }
+        ''', 10)
 
         """  # Unsupported
-        jsi = JSInterpreter('''
-        function x() {
-            if (0!=0) {return 1}
-            else if (1==0) {return 2}
-            else {return 10}
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
+        self._test('''
+            function f() {
+                if (0!=0) {return 1}
+                else if (1==0) {return 2}
+                else {return 10}
+            }
+        ''', 10)
         """
 
     def test_for_loop(self):
-        jsi = JSInterpreter('''
-        function x() { a=0; for (i=0; i-10; i++) {a++} return a }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 10)
+        self._test('function f() { a=0; for (i=0; i-10; i++) {a++} return a }', 10)
 
     def test_switch(self):
         jsi = JSInterpreter('''
-        function x(f) { switch(f){
-            case 1:f+=1;
-            case 2:f+=2;
-            case 3:f+=3;break;
-            case 4:f+=4;
-            default:f=0;
-        } return f }
+            function f(x) { switch(x){
+                case 1:x+=1;
+                case 2:x+=2;
+                case 3:x+=3;break;
+                case 4:x+=4;
+                default:x=0;
+            } return x }
         ''')
-        self.assertEqual(jsi.call_function('x', 1), 7)
-        self.assertEqual(jsi.call_function('x', 3), 6)
-        self.assertEqual(jsi.call_function('x', 5), 0)
+        self.assertEqual(jsi.call_function('f', 1), 7)
+        self.assertEqual(jsi.call_function('f', 3), 6)
+        self.assertEqual(jsi.call_function('f', 5), 0)
 
     def test_switch_default(self):
         jsi = JSInterpreter('''
-        function x(f) { switch(f){
-            case 2: f+=2;
-            default: f-=1;
-            case 5:
-            case 6: f+=6;
-            case 0: break;
-            case 1: f+=1;
-        } return f }
+            function f(x) { switch(x){
+                case 2: x+=2;
+                default: x-=1;
+                case 5:
+                case 6: x+=6;
+                case 0: break;
+                case 1: x+=1;
+            } return x }
         ''')
-        self.assertEqual(jsi.call_function('x', 1), 2)
-        self.assertEqual(jsi.call_function('x', 5), 11)
-        self.assertEqual(jsi.call_function('x', 9), 14)
+        self.assertEqual(jsi.call_function('f', 1), 2)
+        self.assertEqual(jsi.call_function('f', 5), 11)
+        self.assertEqual(jsi.call_function('f', 9), 14)
 
     def test_try(self):
-        jsi = JSInterpreter('''
-        function x() { try{return 10} catch(e){return 5} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 10)
+        self._test('function f() { try{return 10} catch(e){return 5} }', 10)
 
     def test_catch(self):
-        jsi = JSInterpreter('''
-        function x() { try{throw 10} catch(e){return 5} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 5)
+        self._test('function f() { try{throw 10} catch(e){return 5} }', 5)
 
     def test_finally(self):
-        jsi = JSInterpreter('''
-        function x() { try{throw 10} finally {return 42} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 42)
-        jsi = JSInterpreter('''
-        function x() { try{throw 10} catch(e){return 5} finally {return 42} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 42)
+        self._test('function f() { try{throw 10} finally {return 42} }', 42)
+        self._test('function f() { try{throw 10} catch(e){return 5} finally {return 42} }', 42)
 
     def test_nested_try(self):
-        jsi = JSInterpreter('''
-        function x() {try {
-            try{throw 10} finally {throw 42}
-            } catch(e){return 5} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 5)
+        self._test('''
+            function f() {try {
+                try{throw 10} finally {throw 42}
+                } catch(e){return 5} }
+        ''', 5)
 
     def test_for_loop_continue(self):
-        jsi = JSInterpreter('''
-        function x() { a=0; for (i=0; i-10; i++) { continue; a++ } return a }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 0)
+        self._test('function f() { a=0; for (i=0; i-10; i++) { continue; a++ } return a }', 0)
 
     def test_for_loop_break(self):
-        jsi = JSInterpreter('''
-        function x() { a=0; for (i=0; i-10; i++) { break; a++ } return a }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 0)
+        self._test('function f() { a=0; for (i=0; i-10; i++) { break; a++ } return a }', 0)
 
     def test_for_loop_try(self):
-        jsi = JSInterpreter('''
-        function x() {
-            for (i=0; i-10; i++) { try { if (i == 5) throw i} catch {return 10} finally {break} };
-            return 42 }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 42)
+        self._test('''
+            function f() {
+                for (i=0; i-10; i++) { try { if (i == 5) throw i} catch {return 10} finally {break} };
+                return 42 }
+        ''', 42)
 
     def test_literal_list(self):
-        jsi = JSInterpreter('''
-        function x() { return [1, 2, "asdf", [5, 6, 7]][3] }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [5, 6, 7])
+        self._test('function f() { return [1, 2, "asdf", [5, 6, 7]][3] }', [5, 6, 7])
 
     def test_comma(self):
-        jsi = JSInterpreter('''
-        function x() { a=5; a -= 1, a+=3; return a }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 7)
-
-        jsi = JSInterpreter('''
-        function x() { a=5; return (a -= 1, a+=3, a); }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 7)
-
-        jsi = JSInterpreter('''
-        function x() { return (l=[0,1,2,3], function(a, b){return a+b})((l[1], l[2]), l[3]) }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 5)
+        self._test('function f() { a=5; a -= 1, a+=3; return a }', 7)
+        self._test('function f() { a=5; return (a -= 1, a+=3, a); }', 7)
+        self._test('function f() { return (l=[0,1,2,3], function(a, b){return a+b})((l[1], l[2]), l[3]) }', 5)
 
     def test_void(self):
-        jsi = JSInterpreter('''
-        function x() { return void 42; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), None)
+        self._test('function f() { return void 42; }', None)
 
     def test_return_function(self):
         jsi = JSInterpreter('''
-        function x() { return [1, function(){return 1}][1] }
+            function f() { return [1, function(){return 1}][1] }
         ''')
-        self.assertEqual(jsi.call_function('x')([]), 1)
+        self.assertEqual(jsi.call_function('f')([]), 1)
 
     def test_null(self):
-        jsi = JSInterpreter('''
-        function x() { return null; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), None)
-
-        jsi = JSInterpreter('''
-        function x() { return [null > 0, null < 0, null == 0, null === 0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, False, False, False])
-
-        jsi = JSInterpreter('''
-        function x() { return [null >= 0, null <= 0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [True, True])
+        self._test('function f() { return null; }', None)
+        self._test('function f() { return [null > 0, null < 0, null == 0, null === 0]; }',
+                   [False, False, False, False])
+        self._test('function f() { return [null >= 0, null <= 0]; }', [True, True])
 
     def test_undefined(self):
-        jsi = JSInterpreter('''
-        function x() { return undefined === undefined; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), True)
-
-        jsi = JSInterpreter('''
-        function x() { return undefined; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), JS_Undefined)
-
-        jsi = JSInterpreter('''
-        function x() { let v; return v; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), JS_Undefined)
-
-        jsi = JSInterpreter('''
-        function x() { return [undefined === undefined, undefined == undefined, undefined < undefined, undefined > undefined]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [True, True, False, False])
-
-        jsi = JSInterpreter('''
-        function x() { return [undefined === 0, undefined == 0, undefined < 0, undefined > 0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, False, False, False])
-
-        jsi = JSInterpreter('''
-        function x() { return [undefined >= 0, undefined <= 0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, False])
-
-        jsi = JSInterpreter('''
-        function x() { return [undefined > null, undefined < null, undefined == null, undefined === null]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, False, True, False])
-
-        jsi = JSInterpreter('''
-        function x() { return [undefined === null, undefined == null, undefined < null, undefined > null]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, True, False, False])
-
-        jsi = JSInterpreter('''
-        function x() { let v; return [42+v, v+42, v**42, 42**v, 0**v]; }
-        ''')
-        for y in jsi.call_function('x'):
+        self._test('function f() { return undefined === undefined; }', True)
+        self._test('function f() { return undefined; }', JS_Undefined)
+        self._test('function f() {return undefined ?? 42; }', 42)
+        self._test('function f() { let v; return v; }', JS_Undefined)
+        self._test('function f() { let v; return v**0; }', 1)
+        self._test('function f() { let v; return [v>42, v<=42, v&&42, 42&&v]; }',
+                   [False, False, JS_Undefined, JS_Undefined])
+
+        self._test('''
+            function f() { return [
+                undefined === undefined,
+                undefined == undefined,
+                undefined == null,
+                undefined < undefined,
+                undefined > undefined,
+                undefined === 0,
+                undefined == 0,
+                undefined < 0,
+                undefined > 0,
+                undefined >= 0,
+                undefined <= 0,
+                undefined > null,
+                undefined < null,
+                undefined === null
+            ]; }
+        ''', list(map(bool, (1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0))))
+
+        jsi = JSInterpreter('''
+            function f() { let v; return [42+v, v+42, v**42, 42**v, 0**v]; }
+        ''')
+        for y in jsi.call_function('f'):
             self.assertTrue(math.isnan(y))
 
-        jsi = JSInterpreter('''
-        function x() { let v; return v**0; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 1)
-
-        jsi = JSInterpreter('''
-        function x() { let v; return [v>42, v<=42, v&&42, 42&&v]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [False, False, JS_Undefined, JS_Undefined])
-
-        jsi = JSInterpreter('function x(){return undefined ?? 42; }')
-        self.assertEqual(jsi.call_function('x'), 42)
-
     def test_object(self):
-        jsi = JSInterpreter('''
-        function x() { return {}; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), {})
-
-        jsi = JSInterpreter('''
-        function x() { let a = {m1: 42, m2: 0 }; return [a["m1"], a.m2]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), [42, 0])
-
-        jsi = JSInterpreter('''
-        function x() { let a; return a?.qq; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), JS_Undefined)
-
-        jsi = JSInterpreter('''
-        function x() { let a = {m1: 42, m2: 0 }; return a?.qq; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), JS_Undefined)
+        self._test('function f() { return {}; }', {})
+        self._test('function f() { let a = {m1: 42, m2: 0 }; return [a["m1"], a.m2]; }', [42, 0])
+        self._test('function f() { let a; return a?.qq; }', JS_Undefined)
+        self._test('function f() { let a = {m1: 42, m2: 0 }; return a?.qq; }', JS_Undefined)
 
     def test_regex(self):
-        jsi = JSInterpreter('''
-        function x() { let a=/,,[/,913,/](,)}/; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), None)
+        self._test('function f() { let a=/,,[/,913,/](,)}/; }', None)
 
-        jsi = JSInterpreter('''
-        function x() { let a=/,,[/,913,/](,)}/; return a; }
-        ''')
-        self.assertIsInstance(jsi.call_function('x'), re.Pattern)
+        jsi = JSInterpreter('function f() { let a=/,,[/,913,/](,)}/; return a; }')
+        self.assertIsInstance(jsi.call_function('f'), re.Pattern)
 
-        jsi = JSInterpreter('''
-        function x() { let a=/,,[/,913,/](,)}/i; return a; }
-        ''')
-        self.assertEqual(jsi.call_function('x').flags & re.I, re.I)
+        jsi = JSInterpreter('function f() { let a=/,,[/,913,/](,)}/i; return a; }')
+        self.assertEqual(jsi.call_function('f').flags & re.I, re.I)
 
-        jsi = JSInterpreter(R'''
-        function x() { let a=/,][}",],()}(\[)/; return a; }
-        ''')
-        self.assertEqual(jsi.call_function('x').pattern, r',][}",],()}(\[)')
+        jsi = JSInterpreter(R'function f() { let a=/,][}",],()}(\[)/; return a; }')
+        self.assertEqual(jsi.call_function('f').pattern, r',][}",],()}(\[)')
 
-        jsi = JSInterpreter(R'''
-        function x() { let a=[/[)\\]/]; return a[0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x').pattern, r'[)\\]')
+        jsi = JSInterpreter(R'function f() { let a=[/[)\\]/]; return a[0]; }')
+        self.assertEqual(jsi.call_function('f').pattern, r'[)\\]')
 
     def test_char_code_at(self):
-        jsi = JSInterpreter('function x(i){return "test".charCodeAt(i)}')
-        self.assertEqual(jsi.call_function('x', 0), 116)
-        self.assertEqual(jsi.call_function('x', 1), 101)
-        self.assertEqual(jsi.call_function('x', 2), 115)
-        self.assertEqual(jsi.call_function('x', 3), 116)
-        self.assertEqual(jsi.call_function('x', 4), None)
-        self.assertEqual(jsi.call_function('x', 'not_a_number'), 116)
+        jsi = JSInterpreter('function f(i){return "test".charCodeAt(i)}')
+        self.assertEqual(jsi.call_function('f', 0), 116)
+        self.assertEqual(jsi.call_function('f', 1), 101)
+        self.assertEqual(jsi.call_function('f', 2), 115)
+        self.assertEqual(jsi.call_function('f', 3), 116)
+        self.assertEqual(jsi.call_function('f', 4), None)
+        self.assertEqual(jsi.call_function('f', 'not_a_number'), 116)
 
     def test_bitwise_operators_overflow(self):
-        jsi = JSInterpreter('function x(){return -524999584 << 5}')
-        self.assertEqual(jsi.call_function('x'), 379882496)
-
-        jsi = JSInterpreter('function x(){return 1236566549 << 5}')
-        self.assertEqual(jsi.call_function('x'), 915423904)
+        self._test('function f(){return -524999584 << 5}', 379882496)
+        self._test('function f(){return 1236566549 << 5}', 915423904)
 
     def test_bitwise_operators_typecast(self):
-        jsi = JSInterpreter('function x(){return null << 5}')
-        self.assertEqual(jsi.call_function('x'), 0)
-
-        jsi = JSInterpreter('function x(){return undefined >> 5}')
-        self.assertEqual(jsi.call_function('x'), 0)
-
-        jsi = JSInterpreter('function x(){return 42 << NaN}')
-        self.assertEqual(jsi.call_function('x'), 42)
+        self._test('function f(){return null << 5}', 0)
+        self._test('function f(){return undefined >> 5}', 0)
+        self._test('function f(){return 42 << NaN}', 42)
 
     def test_negative(self):
-        jsi = JSInterpreter("function f(){return 2    *    -2.0;}")
-        self.assertEqual(jsi.call_function('f'), -4)
-
-        jsi = JSInterpreter('function f(){return 2    -    - -2;}')
-        self.assertEqual(jsi.call_function('f'), 0)
-
-        jsi = JSInterpreter('function f(){return 2    -    - - -2;}')
-        self.assertEqual(jsi.call_function('f'), 4)
-
-        jsi = JSInterpreter('function f(){return 2    -    + + - -2;}')
-        self.assertEqual(jsi.call_function('f'), 0)
-
-        jsi = JSInterpreter('function f(){return 2    +    - + - -2;}')
-        self.assertEqual(jsi.call_function('f'), 0)
+        self._test('function f(){return 2    *    -2.0    ;}', -4)
+        self._test('function f(){return 2    -    - -2    ;}', 0)
+        self._test('function f(){return 2    -    - - -2  ;}', 4)
+        self._test('function f(){return 2    -    + + - -2;}', 0)
+        self._test('function f(){return 2    +    - + - -2;}', 0)
 
 
 if __name__ == '__main__':
diff --git a/yt_dlp/YoutubeDL.py b/yt_dlp/YoutubeDL.py
index 8f52a71a9..91aec1fe6 100644
--- a/yt_dlp/YoutubeDL.py
+++ b/yt_dlp/YoutubeDL.py
@@ -13,6 +13,7 @@ import os
 import random
 import re
 import shutil
+import string
 import subprocess
 import sys
 import tempfile
@@ -21,7 +22,6 @@ import tokenize
 import traceback
 import unicodedata
 import urllib.request
-from string import Formatter, ascii_letters
 
 from .cache import Cache
 from .compat import compat_os_name, compat_shlex_quote
@@ -1079,7 +1079,7 @@ class YoutubeDL:
         # correspondingly that is not what we want since we need to keep
         # '%%' intact for template dict substitution step. Working around
         # with boundary-alike separator hack.
-        sep = ''.join(random.choices(ascii_letters, k=32))
+        sep = ''.join(random.choices(string.ascii_letters, k=32))
         outtmpl = outtmpl.replace('%%', f'%{sep}%').replace('$$', f'${sep}$')
 
         # outtmpl should be expand_path'ed before template dict substitution
@@ -1238,7 +1238,7 @@ class YoutubeDL:
                 return list(obj)
             return repr(obj)
 
-        class _ReplacementFormatter(Formatter):
+        class _ReplacementFormatter(string.Formatter):
             def get_field(self, field_name, args, kwargs):
                 if field_name.isdigit():
                     return args[0], -1
@@ -2068,86 +2068,86 @@ class YoutubeDL:
 
         def _parse_filter(tokens):
             filter_parts = []
-            for type, string, start, _, _ in tokens:
-                if type == tokenize.OP and string == ']':
+            for type, string_, start, _, _ in tokens:
+                if type == tokenize.OP and string_ == ']':
                     return ''.join(filter_parts)
                 else:
-                    filter_parts.append(string)
+                    filter_parts.append(string_)
 
         def _remove_unused_ops(tokens):
             # Remove operators that we don't use and join them with the surrounding strings.
             # E.g. 'mp4' '-' 'baseline' '-' '16x9' is converted to 'mp4-baseline-16x9'
             ALLOWED_OPS = ('/', '+', ',', '(', ')')
             last_string, last_start, last_end, last_line = None, None, None, None
-            for type, string, start, end, line in tokens:
-                if type == tokenize.OP and string == '[':
+            for type, string_, start, end, line in tokens:
+                if type == tokenize.OP and string_ == '[':
                     if last_string:
                         yield tokenize.NAME, last_string, last_start, last_end, last_line
                         last_string = None
-                    yield type, string, start, end, line
+                    yield type, string_, start, end, line
                     # everything inside brackets will be handled by _parse_filter
-                    for type, string, start, end, line in tokens:
-                        yield type, string, start, end, line
-                        if type == tokenize.OP and string == ']':
+                    for type, string_, start, end, line in tokens:
+                        yield type, string_, start, end, line
+                        if type == tokenize.OP and string_ == ']':
                             break
-                elif type == tokenize.OP and string in ALLOWED_OPS:
+                elif type == tokenize.OP and string_ in ALLOWED_OPS:
                     if last_string:
                         yield tokenize.NAME, last_string, last_start, last_end, last_line
                         last_string = None
-                    yield type, string, start, end, line
+                    yield type, string_, start, end, line
                 elif type in [tokenize.NAME, tokenize.NUMBER, tokenize.OP]:
                     if not last_string:
-                        last_string = string
+                        last_string = string_
                         last_start = start
                         last_end = end
                     else:
-                        last_string += string
+                        last_string += string_
             if last_string:
                 yield tokenize.NAME, last_string, last_start, last_end, last_line
 
         def _parse_format_selection(tokens, inside_merge=False, inside_choice=False, inside_group=False):
             selectors = []
             current_selector = None
-            for type, string, start, _, _ in tokens:
+            for type, string_, start, _, _ in tokens:
                 # ENCODING is only defined in python 3.x
                 if type == getattr(tokenize, 'ENCODING', None):
                     continue
                 elif type in [tokenize.NAME, tokenize.NUMBER]:
-                    current_selector = FormatSelector(SINGLE, string, [])
+                    current_selector = FormatSelector(SINGLE, string_, [])
                 elif type == tokenize.OP:
-                    if string == ')':
+                    if string_ == ')':
                         if not inside_group:
                             # ')' will be handled by the parentheses group
                             tokens.restore_last_token()
                         break
-                    elif inside_merge and string in ['/', ',']:
+                    elif inside_merge and string_ in ['/', ',']:
                         tokens.restore_last_token()
                         break
-                    elif inside_choice and string == ',':
+                    elif inside_choice and string_ == ',':
                         tokens.restore_last_token()
                         break
-                    elif string == ',':
+                    elif string_ == ',':
                         if not current_selector:
                             raise syntax_error('"," must follow a format selector', start)
                         selectors.append(current_selector)
                         current_selector = None
-                    elif string == '/':
+                    elif string_ == '/':
                         if not current_selector:
                             raise syntax_error('"/" must follow a format selector', start)
                         first_choice = current_selector
                         second_choice = _parse_format_selection(tokens, inside_choice=True)
                         current_selector = FormatSelector(PICKFIRST, (first_choice, second_choice), [])
-                    elif string == '[':
+                    elif string_ == '[':
                         if not current_selector:
                             current_selector = FormatSelector(SINGLE, 'best', [])
                         format_filter = _parse_filter(tokens)
                         current_selector.filters.append(format_filter)
-                    elif string == '(':
+                    elif string_ == '(':
                         if current_selector:
                             raise syntax_error('Unexpected "("', start)
                         group = _parse_format_selection(tokens, inside_group=True)
                         current_selector = FormatSelector(GROUP, group, [])
-                    elif string == '+':
+                    elif string_ == '+':
                         if not current_selector:
                             raise syntax_error('Unexpected "+"', start)
                         selector_1 = current_selector
@@ -2156,7 +2156,7 @@ class YoutubeDL:
                             raise syntax_error('Expected a selector', start)
                         current_selector = FormatSelector(MERGE, (selector_1, selector_2), [])
                     else:
-                        raise syntax_error(f'Operator not recognized: "{string}"', start)
+                        raise syntax_error(f'Operator not recognized: "{string_}"', start)
                 elif type == tokenize.ENDMARKER:
                     break
             if current_selector:
@@ -2898,7 +2898,7 @@ class YoutubeDL:
 
             fmt = '%({})s'
             if tmpl.startswith('{'):
-                tmpl = f'.{tmpl}'
+                tmpl, fmt = f'.{tmpl}', '%({})j'
             if tmpl.endswith('='):
                 tmpl, fmt = tmpl[:-1], '{0} = %({0})#j'
             return '\n'.join(map(fmt.format, [tmpl] if mobj.group('dict') else tmpl.split(',')))
@@ -2937,7 +2937,8 @@ class YoutubeDL:
         print_field('url', 'urls')
         print_field('thumbnail', optional=True)
         print_field('description', optional=True)
-        print_field('filename', optional=True)
+        if filename:
+            print_field('filename')
         if self.params.get('forceduration') and info_copy.get('duration') is not None:
             self.to_stdout(formatSeconds(info_copy['duration']))
         print_field('format')
@@ -3419,8 +3420,8 @@ class YoutubeDL:
         if remove_private_keys:
             reject = lambda k, v: v is None or k.startswith('__') or k in {
                 'requested_downloads', 'requested_formats', 'requested_subtitles', 'requested_entries',
-                'entries', 'filepath', '_filename', 'infojson_filename', 'original_url', 'playlist_autonumber',
-                '_format_sort_fields',
+                'entries', 'filepath', '_filename', 'filename', 'infojson_filename', 'original_url',
+                'playlist_autonumber', '_format_sort_fields',
             }
         else:
             reject = lambda k, v: False
@@ -3489,7 +3490,7 @@ class YoutubeDL:
                 *files_to_delete, info=infodict, msg='Deleting original file %s (pass -k to keep)')
         return infodict
 
-    def run_all_pps(self, key, info, *, additional_pps=None, fatal=True):
+    def run_all_pps(self, key, info, *, additional_pps=None):
         if key != 'video':
             self._forceprint(key, info)
         for pp in (additional_pps or []) + self._pps[key]:
diff --git a/yt_dlp/jsinterp.py b/yt_dlp/jsinterp.py
index 965b1c0f2..82974fb27 100644
--- a/yt_dlp/jsinterp.py
+++ b/yt_dlp/jsinterp.py
@@ -248,7 +248,7 @@ class JSInterpreter:
             return
         counters = {k: 0 for k in _MATCHING_PARENS.values()}
         start, splits, pos, delim_len = 0, 0, 0, len(delim) - 1
-        in_quote, escaping, after_op, in_regex_char_group, in_unary_op = None, False, True, False, False
+        in_quote, escaping, after_op, in_regex_char_group = None, False, True, False
         for idx, char in enumerate(expr):
             if not in_quote and char in _MATCHING_PARENS:
                 counters[_MATCHING_PARENS[char]] += 1
diff --git a/yt_dlp/utils.py b/yt_dlp/utils.py
index 47aa75c47..190af1b7d 100644
--- a/yt_dlp/utils.py
+++ b/yt_dlp/utils.py
@@ -3281,7 +3281,7 @@ def is_iterable_like(x, allowed_types=collections.abc.Iterable, blocked_types=NO
 
 
 def variadic(x, allowed_types=NO_DEFAULT):
-    return x if is_iterable_like(x, blocked_types=allowed_types) else (x,)
+    return x if is_iterable_like(x, blocked_types=allowed_types) else (x, )
 
 
 def dict_get(d, key_or_keys, default=None, skip_false_values=True):
@@ -5404,7 +5404,7 @@ def to_high_limit_path(path):
 
 def format_field(obj, field=None, template='%s', ignore=NO_DEFAULT, default='', func=IDENTITY):
     val = traverse_obj(obj, *variadic(field))
-    if (not val and val != 0) if ignore is NO_DEFAULT else val in variadic(ignore):
+    if not val if ignore is NO_DEFAULT else val in variadic(ignore):
         return default
     return template % func(val)
 
@@ -5704,8 +5704,8 @@ def traverse_dict(dictn, keys, casesense=True):
     return traverse_obj(dictn, keys, casesense=casesense, is_user_input=True, traverse_string=True)
 
 
-def get_first(obj, keys, **kwargs):
-    return traverse_obj(obj, (..., *variadic(keys)), **kwargs, get_all=False)
+def get_first(obj, *paths, **kwargs):
+    return traverse_obj(obj, *((..., *variadic(keys)) for keys in paths), **kwargs, get_all=False)
 
 
 def time_seconds(**kwargs):