[jsinterp] Re-align JSInterp and tests (esp.) with yt-dlp

Thx: various yt-dlp authors

2 files changed, 273 insertions, 465 deletions

diff --git a/test/test_jsinterp.py b/test/test_jsinterp.py
index da8e98020..86d7f0d46 100644
--- a/test/test_jsinterp.py
+++ b/test/test_jsinterp.py
@@ -11,194 +11,146 @@ sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 import math
 import re
 
+from youtube_dl.compat import compat_str
 from youtube_dl.jsinterp import JS_Undefined, JSInterpreter
 
+NaN = object()
 
-class TestJSInterpreter(unittest.TestCase):
-    def test_basic(self):
-        jsi = JSInterpreter('function x(){;}')
-        self.assertEqual(jsi.call_function('x'), None)
-        self.assertEqual(repr(jsi.extract_function('x')), 'F<x>')
-
-        jsi = JSInterpreter('function x3(){return 42;}')
-        self.assertEqual(jsi.call_function('x3'), 42)
 
-        jsi = JSInterpreter('function x3(){42}')
-        self.assertEqual(jsi.call_function('x3'), None)
+class TestJSInterpreter(unittest.TestCase):
+    def _test(self, jsi_or_code, expected, func='f', args=()):
+        if isinstance(jsi_or_code, compat_str):
+            jsi_or_code = JSInterpreter(jsi_or_code)
+        got = jsi_or_code.call_function(func, *args)
+        if expected is NaN:
+            self.assertTrue(math.isnan(got), '{0} is not NaN'.format(got))
+        else:
+            self.assertEqual(got, expected)
 
-        jsi = JSInterpreter('var x5 = function(){return 42;}')
-        self.assertEqual(jsi.call_function('x5'), 42)
+    def test_basic(self):
+        jsi = JSInterpreter('function f(){;}')
+        self.assertEqual(repr(jsi.extract_function('f')), 'F<f>')
+        self._test(jsi, None)
 
-    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(){return 42;}', 42)
+        self._test('function f(){42}', None)
+        self._test('var f = function(){return 42;}', 42)
 
     def test_add(self):
-        jsi = JSInterpreter('function f(){return 42 + 7;}')
-        self.assertEqual(jsi.call_function('f'), 49)
-        jsi = JSInterpreter('function f(){return 42 + undefined;}')
-        self.assertTrue(math.isnan(jsi.call_function('f')))
-        jsi = JSInterpreter('function f(){return 42 + null;}')
-        self.assertEqual(jsi.call_function('f'), 42)
+        self._test('function f(){return 42 + 7;}', 49)
+        self._test('function f(){return 42 + undefined;}', NaN)
+        self._test('function f(){return 42 + null;}', 42)
 
     def test_sub(self):
-        jsi = JSInterpreter('function f(){return 42 - 7;}')
-        self.assertEqual(jsi.call_function('f'), 35)
-        jsi = JSInterpreter('function f(){return 42 - undefined;}')
-        self.assertTrue(math.isnan(jsi.call_function('f')))
-        jsi = JSInterpreter('function f(){return 42 - null;}')
-        self.assertEqual(jsi.call_function('f'), 42)
+        self._test('function f(){return 42 - 7;}', 35)
+        self._test('function f(){return 42 - undefined;}', NaN)
+        self._test('function f(){return 42 - null;}', 42)
 
     def test_mul(self):
-        jsi = JSInterpreter('function f(){return 42 * 7;}')
-        self.assertEqual(jsi.call_function('f'), 294)
-        jsi = JSInterpreter('function f(){return 42 * undefined;}')
-        self.assertTrue(math.isnan(jsi.call_function('f')))
-        jsi = JSInterpreter('function f(){return 42 * null;}')
-        self.assertEqual(jsi.call_function('f'), 0)
+        self._test('function f(){return 42 * 7;}', 294)
+        self._test('function f(){return 42 * undefined;}', NaN)
+        self._test('function f(){return 42 * null;}', 0)
 
     def test_div(self):
         jsi = JSInterpreter('function f(a, b){return a / b;}')
-        self.assertTrue(math.isnan(jsi.call_function('f', 0, 0)))
-        self.assertTrue(math.isnan(jsi.call_function('f', JS_Undefined, 1)))
-        self.assertTrue(math.isinf(jsi.call_function('f', 2, 0)))
-        self.assertEqual(jsi.call_function('f', 0, 3), 0)
+        self._test(jsi, NaN, args=(0, 0))
+        self._test(jsi, NaN, args=(JS_Undefined, 1))
+        self._test(jsi, float('inf'), args=(2, 0))
+        self._test(jsi, 0, args=(0, 3))
 
     def test_mod(self):
-        jsi = JSInterpreter('function f(){return 42 % 7;}')
-        self.assertEqual(jsi.call_function('f'), 0)
-        jsi = JSInterpreter('function f(){return 42 % 0;}')
-        self.assertTrue(math.isnan(jsi.call_function('f')))
-        jsi = JSInterpreter('function f(){return 42 % undefined;}')
-        self.assertTrue(math.isnan(jsi.call_function('f')))
+        self._test('function f(){return 42 % 7;}', 0)
+        self._test('function f(){return 42 % 0;}', NaN)
+        self._test('function f(){return 42 % undefined;}', NaN)
 
     def test_exp(self):
-        jsi = JSInterpreter('function f(){return 42 ** 2;}')
-        self.assertEqual(jsi.call_function('f'), 1764)
-        jsi = JSInterpreter('function f(){return 42 ** undefined;}')
-        self.assertTrue(math.isnan(jsi.call_function('f')))
-        jsi = JSInterpreter('function f(){return 42 ** null;}')
-        self.assertEqual(jsi.call_function('f'), 1)
-        jsi = JSInterpreter('function f(){return undefined ** 42;}')
-        self.assertTrue(math.isnan(jsi.call_function('f')))
+        self._test('function f(){return 42 ** 2;}', 1764)
+        self._test('function f(){return 42 ** undefined;}', NaN)
+        self._test('function f(){return 42 ** null;}', 1)
+        self._test('function f(){return undefined ** 42;}', NaN)
+
+    def test_calc(self):
+        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)
+        # https://github.com/ytdl-org/youtube-dl/issues/32815
+        self._test('function f(){return 0  - 7 * - 6;}', 42)
 
     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)
 
+    @unittest.skip('Not yet fully implemented')
     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')))
+        self._test('function f() { return NaN }', NaN)
 
     def test_Date(self):
-        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)
 
+        jsi = JSInterpreter('function f(dt) { return new Date(dt) - 0; }')
         # date format m/d/y
-        self.assertEqual(jsi.call_function('x', '12/31/1969 18:01:26 MDT'), 86000)
-
+        self._test(jsi, 86000, args=['12/31/1969 18:01:26 MDT'])
         # epoch 0
-        self.assertEqual(jsi.call_function('x', '1 January 1970 00:00:00 UTC'), 0)
+        self._test(jsi, 0, args=['1 January 1970 00:00:00 UTC'])
 
     def test_call(self):
         jsi = JSInterpreter('''
@@ -206,179 +158,115 @@ class TestJSInterpreter(unittest.TestCase):
         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)
+        self._test(jsi, 5, func='z')
+        self._test(jsi, 2, func='y')
 
     def test_if(self):
-        jsi = JSInterpreter('''
-        function x() {
+        self._test('''
+            function f() {
             let a = 9;
             if (0==0) {a++}
             return a
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
+            }
+        ''', 10)
 
-        jsi = JSInterpreter('''
-        function x() {
+        self._test('''
+            function f() {
             if (0==0) {return 10}
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
+            }
+        ''', 10)
 
-        jsi = JSInterpreter('''
-        function x() {
+        self._test('''
+            function f() {
             if (0!=0) {return 1}
             else {return 10}
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
-
-        """  # Unsupported
-        jsi = JSInterpreter('''
-        function x() {
-            if (0!=0) return 1;
-            else {return 10}
-        }''')
-        self.assertEqual(jsi.call_function('x'), 10)
-        """
+            }
+        ''', 10)
 
     def test_elseif(self):
-        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)
-
-        """  # 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)
-        # etc
-        """
+        self._test('''
+            function f() {
+                if (0!=0) {return 1}
+                else if (1==0) {return 2}
+                else {return 10}
+            }
+        ''', 10)
 
     def test_for_loop(self):
-        # function x() { a=0; for (i=0; i-10; i++) {a++} a }
-        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_while_loop(self):
-        # function x() { a=0; while (a<10) {a++} a }
-        jsi = JSInterpreter('''
-        function x() { a=0; while (a<10) {a++} return a }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 10)
+        self._test('function f() { a=0; while (a<10) {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._test(jsi, 7, args=[1])
+        self._test(jsi, 6, args=[3])
+        self._test(jsi, 0, args=[5])
 
     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._test(jsi, 2, args=[1])
+        self._test(jsi, 11, args=[5])
+        self._test(jsi, 14, args=[9])
 
     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}
+        self._test('''
+            function f() {try {
+                try{throw 10} finally {throw 42}
             } catch(e){return 5} }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 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('''
@@ -387,110 +275,60 @@ class TestJSInterpreter(unittest.TestCase):
         self.assertEqual(jsi.call_function('x')([]), 1)
 
     def test_null(self):
-        jsi = JSInterpreter('''
-        function x() { return null; }
-        ''')
-        self.assertIs(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.assertTrue(jsi.call_function('x'))
-
-        jsi = JSInterpreter('''
-        function x() { return undefined; }
-        ''')
-        self.assertIs(jsi.call_function('x'), JS_Undefined)
-
-        jsi = JSInterpreter('''
-        function x() { let v; return v; }
-        ''')
-        self.assertIs(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]; }
+        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
+            ]; }
+        ''', [True] * 3)
+        self._test('''
+            function f() { return [
+                undefined < undefined,
+                undefined > undefined,
+                undefined === 0,
+                undefined == 0,
+                undefined < 0,
+                undefined > 0,
+                undefined >= 0,
+                undefined <= 0,
+                undefined > null,
+                undefined < null,
+                undefined === null
+            ]; }
+        ''', [False] * 11)
+
+        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.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.assertIs(jsi.call_function('x'), JS_Undefined)
-
-        jsi = JSInterpreter('''
-        function x() { let a = {m1: 42, m2: 0 }; return a?.qq; }
-        ''')
-        self.assertIs(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.assertIs(jsi.call_function('x'), None)
+        self._test('function f() { let a=/,,[/,913,/](,)}/; }', None)
 
         jsi = JSInterpreter('''
-        function x() { let a=/,,[/,913,/](,)}/; "".replace(a, ""); return a; }
+            function x() { let a=/,,[/,913,/](,)}/; "".replace(a, ""); return a; }
         ''')
         attrs = set(('findall', 'finditer', 'match', 'scanner', 'search',
                      'split', 'sub', 'subn'))
@@ -500,94 +338,65 @@ class TestJSInterpreter(unittest.TestCase):
         self.assertSetEqual(set(dir(jsi.call_function('x'))) & attrs, attrs)
 
         jsi = JSInterpreter('''
-        function x() { let a=/,,[/,913,/](,)}/i; return a; }
+            function x() { let a=/,,[/,913,/](,)}/i; return a; }
         ''')
         self.assertEqual(jsi.call_function('x').flags & ~re.U, re.I)
 
-        jsi = JSInterpreter(r'''
-        function x() { let a="data-name".replace("data-", ""); return a }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 'name')
-
-        jsi = JSInterpreter(r'''
-        function x() { let a="data-name".replace(new RegExp("^.+-"), ""); return a; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 'name')
-
-        jsi = JSInterpreter(r'''
-        function x() { let a="data-name".replace(/^.+-/, ""); return a; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 'name')
-
-        jsi = JSInterpreter(r'''
-        function x() { let a="data-name".replace(/a/g, "o"); return a; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 'doto-nome')
-
-        jsi = JSInterpreter(r'''
-        function x() { let a="data-name".replaceAll("a", "o"); return a; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 'doto-nome')
+        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'[)\\]')
 
-        """  # fails
-        jsi = JSInterpreter(r'''
-        function x() { let a=100; a/=/[0-9]+/.exec('divide by 20 today')[0]; }
-        ''')
-        self.assertEqual(jsi.call_function('x'), 5)
-        """
+    def test_replace(self):
+        self._test('function f() { let a="data-name".replace("data-", ""); return a }',
+                   'name')
+        self._test('function f() { let a="data-name".replace(new RegExp("^.+-"), ""); return a; }',
+                   'name')
+        self._test('function f() { let a="data-name".replace(/^.+-/, ""); return a; }',
+                   'name')
+        self._test('function f() { let a="data-name".replace(/a/g, "o"); return a; }',
+                   'doto-nome')
+        self._test('function f() { let a="data-name".replaceAll("a", "o"); return a; }',
+                   'doto-nome')
 
     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._test(jsi, 116, args=[0])
+        self._test(jsi, 101, args=[1])
+        self._test(jsi, 115, args=[2])
+        self._test(jsi, 116, args=[3])
+        self._test(jsi, None, args=[4])
+        self._test(jsi, 116, args=['not_a_number'])
 
     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)
-
-    def test_bitwise_operators_madness(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)
-
-        jsi = JSInterpreter('function x(){return 42 << Infinity}')
-        self.assertEqual(jsi.call_function('x'), 42)
+        self._test('function f(){return -524999584 << 5}', 379882496)
+        self._test('function f(){return 1236566549 << 5}', 915423904)
+
+    def test_bitwise_operators_typecast(self):
+        # madness
+        self._test('function f(){return null << 5}', 0)
+        self._test('function f(){return undefined >> 5}', 0)
+        self._test('function f(){return 42 << NaN}', 42)
+        self._test('function f(){return 42 << Infinity}', 42)
+
+    def test_negative(self):
+        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)
 
     def test_32066(self):
-        jsi = JSInterpreter("function x(){return Math.pow(3, 5) + new Date('1970-01-01T08:01:42.000+08:00') / 1000 * -239 - -24205;}")
-        self.assertEqual(jsi.call_function('x'), 70)
-
-    def test_unary_operators(self):
-        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)
-        # https://github.com/ytdl-org/youtube-dl/issues/32815
-        jsi = JSInterpreter('function f(){return 0  - 7 * - 6;}')
-        self.assertEqual(jsi.call_function('f'), 42)
+        self._test(
+            "function f(){return Math.pow(3, 5) + new Date('1970-01-01T08:01:42.000+08:00') / 1000 * -239 - -24205;}",
+            70)
 
-    """ # fails so far
+    @unittest.skip('Not yet working')
     def test_packed(self):
-        jsi = JSInterpreter('''function x(p,a,c,k,e,d){while(c--)if(k[c])p=p.replace(new RegExp('\\b'+c.toString(a)+'\\b','g'),k[c]);return p}''')
-        self.assertEqual(jsi.call_function('x', '''h 7=g("1j");7.7h({7g:[{33:"w://7f-7e-7d-7c.v.7b/7a/79/78/77/76.74?t=73&s=2s&e=72&f=2t&71=70.0.0.1&6z=6y&6x=6w"}],6v:"w://32.v.u/6u.31",16:"r%",15:"r%",6t:"6s",6r:"",6q:"l",6p:"l",6o:"6n",6m:\'6l\',6k:"6j",9:[{33:"/2u?b=6i&n=50&6h=w://32.v.u/6g.31",6f:"6e"}],1y:{6d:1,6c:\'#6b\',6a:\'#69\',68:"67",66:30,65:r,},"64":{63:"%62 2m%m%61%5z%5y%5x.u%5w%5v%5u.2y%22 2k%m%1o%22 5t%m%1o%22 5s%m%1o%22 2j%m%5r%22 16%m%5q%22 15%m%5p%22 5o%2z%5n%5m%2z",5l:"w://v.u/d/1k/5k.2y",5j:[]},\'5i\':{"5h":"5g"},5f:"5e",5d:"w://v.u",5c:{},5b:l,1x:[0.25,0.50,0.75,1,1.25,1.5,2]});h 1m,1n,5a;h 59=0,58=0;h 7=g("1j");h 2x=0,57=0,56=0;$.55({54:{\'53-52\':\'2i-51\'}});7.j(\'4z\',6(x){c(5>0&&x.1l>=5&&1n!=1){1n=1;$(\'q.4y\').4x(\'4w\')}});7.j(\'13\',6(x){2x=x.1l});7.j(\'2g\',6(x){2w(x)});7.j(\'4v\',6(){$(\'q.2v\').4u()});6 2w(x){$(\'q.2v\').4t();c(1m)19;1m=1;17=0;c(4s.4r===l){17=1}$.4q(\'/2u?b=4p&2l=1k&4o=2t-4n-4m-2s-4l&4k=&4j=&4i=&17=\'+17,6(2r){$(\'#4h\').4g(2r)});$(\'.3-8-4f-4e:4d("4c")\').2h(6(e){2q();g().4b(0);g().4a(l)});6 2q(){h $14=$("<q />").2p({1l:"49",16:"r%",15:"r%",48:0,2n:0,2o:47,46:"45(10%, 10%, 10%, 0.4)","44-43":"42"});$("<41 />").2p({16:"60%",15:"60%",2o:40,"3z-2n":"3y"}).3x({\'2m\':\'/?b=3w&2l=1k\',\'2k\':\'0\',\'2j\':\'2i\'}).2f($14);$14.2h(6(){$(3v).3u();g().2g()});$14.2f($(\'#1j\'))}g().13(0);}6 3t(){h 9=7.1b(2e);2d.2c(9);c(9.n>1){1r(i=0;i<9.n;i++){c(9[i].1a==2e){2d.2c(\'!!=\'+i);7.1p(i)}}}}7.j(\'3s\',6(){g().1h("/2a/3r.29","3q 10 28",6(){g().13(g().27()+10)},"2b");$("q[26=2b]").23().21(\'.3-20-1z\');g().1h("/2a/3p.29","3o 10 28",6(){h 12=g().27()-10;c(12<0)12=0;g().13(12)},"24");$("q[26=24]").23().21(\'.3-20-1z\');});6 1i(){}7.j(\'3n\',6(){1i()});7.j(\'3m\',6(){1i()});7.j("k",6(y){h 9=7.1b();c(9.n<2)19;$(\'.3-8-3l-3k\').3j(6(){$(\'#3-8-a-k\').1e(\'3-8-a-z\');$(\'.3-a-k\').p(\'o-1f\',\'11\')});7.1h("/3i/3h.3g","3f 3e",6(){$(\'.3-1w\').3d(\'3-8-1v\');$(\'.3-8-1y, .3-8-1x\').p(\'o-1g\',\'11\');c($(\'.3-1w\').3c(\'3-8-1v\')){$(\'.3-a-k\').p(\'o-1g\',\'l\');$(\'.3-a-k\').p(\'o-1f\',\'l\');$(\'.3-8-a\').1e(\'3-8-a-z\');$(\'.3-8-a:1u\').3b(\'3-8-a-z\')}3a{$(\'.3-a-k\').p(\'o-1g\',\'11\');$(\'.3-a-k\').p(\'o-1f\',\'11\');$(\'.3-8-a:1u\').1e(\'3-8-a-z\')}},"39");7.j("38",6(y){1d.37(\'1c\',y.9[y.36].1a)});c(1d.1t(\'1c\')){35("1s(1d.1t(\'1c\'));",34)}});h 18;6 1s(1q){h 9=7.1b();c(9.n>1){1r(i=0;i<9.n;i++){c(9[i].1a==1q){c(i==18){19}18=i;7.1p(i)}}}}',36,270,'|||jw|||function|player|settings|tracks|submenu||if||||jwplayer|var||on|audioTracks|true|3D|length|aria|attr|div|100|||sx|filemoon|https||event|active||false|tt|seek|dd|height|width|adb|current_audio|return|name|getAudioTracks|default_audio|localStorage|removeClass|expanded|checked|addButton|callMeMaybe|vplayer|0fxcyc2ajhp1|position|vvplay|vvad|220|setCurrentAudioTrack|audio_name|for|audio_set|getItem|last|open|controls|playbackRates|captions|rewind|icon|insertAfter||detach|ff00||button|getPosition|sec|png|player8|ff11|log|console|track_name|appendTo|play|click|no|scrolling|frameborder|file_code|src|top|zIndex|css|showCCform|data|1662367683|383371|dl|video_ad|doPlay|prevt|mp4|3E||jpg|thumbs|file|300|setTimeout|currentTrack|setItem|audioTrackChanged|dualSound|else|addClass|hasClass|toggleClass|Track|Audio|svg|dualy|images|mousedown|buttons|topbar|playAttemptFailed|beforePlay|Rewind|fr|Forward|ff|ready|set_audio_track|remove|this|upload_srt|prop|50px|margin|1000001|iframe|center|align|text|rgba|background|1000000|left|absolute|pause|setCurrentCaptions|Upload|contains|item|content|html|fviews|referer|prem|embed|3e57249ef633e0d03bf76ceb8d8a4b65|216|83|hash|view|get|TokenZir|window|hide|show|complete|slow|fadeIn|video_ad_fadein|time||cache|Cache|Content|headers|ajaxSetup|v2done|tott|vastdone2|vastdone1|vvbefore|playbackRateControls|cast|aboutlink|FileMoon|abouttext|UHD|1870|qualityLabels|sites|GNOME_POWER|link|2Fiframe|3C|allowfullscreen|22360|22640|22no|marginheight|marginwidth|2FGNOME_POWER|2F0fxcyc2ajhp1|2Fe|2Ffilemoon|2F|3A||22https|3Ciframe|code|sharing|fontOpacity|backgroundOpacity|Tahoma|fontFamily|303030|backgroundColor|FFFFFF|color|userFontScale|thumbnails|kind|0fxcyc2ajhp10000|url|get_slides|start|startparam|none|preload|html5|primary|hlshtml|androidhls|duration|uniform|stretching|0fxcyc2ajhp1_xt|image|2048|sp|6871|asn|127|srv|43200|_g3XlBcu2lmD9oDexD2NLWSmah2Nu3XcDrl93m9PwXY|m3u8||master|0fxcyc2ajhp1_x|00076|01|hls2|to|s01|delivery|storage|moon|sources|setup'''.split('|')))
-    """
+        self._test(
+            '''function f(p,a,c,k,e,d){while(c--)if(k[c])p=p.replace(new RegExp('\\b'+c.toString(a)+'\\b','g'),k[c]);return p}''',
+            '''h 7=g("1j");7.7h({7g:[{33:"w://7f-7e-7d-7c.v.7b/7a/79/78/77/76.74?t=73&s=2s&e=72&f=2t&71=70.0.0.1&6z=6y&6x=6w"}],6v:"w://32.v.u/6u.31",16:"r%",15:"r%",6t:"6s",6r:"",6q:"l",6p:"l",6o:"6n",6m:\'6l\',6k:"6j",9:[{33:"/2u?b=6i&n=50&6h=w://32.v.u/6g.31",6f:"6e"}],1y:{6d:1,6c:\'#6b\',6a:\'#69\',68:"67",66:30,65:r,},"64":{63:"%62 2m%m%61%5z%5y%5x.u%5w%5v%5u.2y%22 2k%m%1o%22 5t%m%1o%22 5s%m%1o%22 2j%m%5r%22 16%m%5q%22 15%m%5p%22 5o%2z%5n%5m%2z",5l:"w://v.u/d/1k/5k.2y",5j:[]},\'5i\':{"5h":"5g"},5f:"5e",5d:"w://v.u",5c:{},5b:l,1x:[0.25,0.50,0.75,1,1.25,1.5,2]});h 1m,1n,5a;h 59=0,58=0;h 7=g("1j");h 2x=0,57=0,56=0;$.55({54:{\'53-52\':\'2i-51\'}});7.j(\'4z\',6(x){c(5>0&&x.1l>=5&&1n!=1){1n=1;$(\'q.4y\').4x(\'4w\')}});7.j(\'13\',6(x){2x=x.1l});7.j(\'2g\',6(x){2w(x)});7.j(\'4v\',6(){$(\'q.2v\').4u()});6 2w(x){$(\'q.2v\').4t();c(1m)19;1m=1;17=0;c(4s.4r===l){17=1}$.4q(\'/2u?b=4p&2l=1k&4o=2t-4n-4m-2s-4l&4k=&4j=&4i=&17=\'+17,6(2r){$(\'#4h\').4g(2r)});$(\'.3-8-4f-4e:4d("4c")\').2h(6(e){2q();g().4b(0);g().4a(l)});6 2q(){h $14=$("<q />").2p({1l:"49",16:"r%",15:"r%",48:0,2n:0,2o:47,46:"45(10%, 10%, 10%, 0.4)","44-43":"42"});$("<41 />").2p({16:"60%",15:"60%",2o:40,"3z-2n":"3y"}).3x({\'2m\':\'/?b=3w&2l=1k\',\'2k\':\'0\',\'2j\':\'2i\'}).2f($14);$14.2h(6(){$(3v).3u();g().2g()});$14.2f($(\'#1j\'))}g().13(0);}6 3t(){h 9=7.1b(2e);2d.2c(9);c(9.n>1){1r(i=0;i<9.n;i++){c(9[i].1a==2e){2d.2c(\'!!=\'+i);7.1p(i)}}}}7.j(\'3s\',6(){g().1h("/2a/3r.29","3q 10 28",6(){g().13(g().27()+10)},"2b");$("q[26=2b]").23().21(\'.3-20-1z\');g().1h("/2a/3p.29","3o 10 28",6(){h 12=g().27()-10;c(12<0)12=0;g().13(12)},"24");$("q[26=24]").23().21(\'.3-20-1z\');});6 1i(){}7.j(\'3n\',6(){1i()});7.j(\'3m\',6(){1i()});7.j("k",6(y){h 9=7.1b();c(9.n<2)19;$(\'.3-8-3l-3k\').3j(6(){$(\'#3-8-a-k\').1e(\'3-8-a-z\');$(\'.3-a-k\').p(\'o-1f\',\'11\')});7.1h("/3i/3h.3g","3f 3e",6(){$(\'.3-1w\').3d(\'3-8-1v\');$(\'.3-8-1y, .3-8-1x\').p(\'o-1g\',\'11\');c($(\'.3-1w\').3c(\'3-8-1v\')){$(\'.3-a-k\').p(\'o-1g\',\'l\');$(\'.3-a-k\').p(\'o-1f\',\'l\');$(\'.3-8-a\').1e(\'3-8-a-z\');$(\'.3-8-a:1u\').3b(\'3-8-a-z\')}3a{$(\'.3-a-k\').p(\'o-1g\',\'11\');$(\'.3-a-k\').p(\'o-1f\',\'11\');$(\'.3-8-a:1u\').1e(\'3-8-a-z\')}},"39");7.j("38",6(y){1d.37(\'1c\',y.9[y.36].1a)});c(1d.1t(\'1c\')){35("1s(1d.1t(\'1c\'));",34)}});h 18;6 1s(1q){h 9=7.1b();c(9.n>1){1r(i=0;i<9.n;i++){c(9[i].1a==1q){c(i==18){19}18=i;7.1p(i)}}}}',36,270,'|||jw|||function|player|settings|tracks|submenu||if||||jwplayer|var||on|audioTracks|true|3D|length|aria|attr|div|100|||sx|filemoon|https||event|active||false|tt|seek|dd|height|width|adb|current_audio|return|name|getAudioTracks|default_audio|localStorage|removeClass|expanded|checked|addButton|callMeMaybe|vplayer|0fxcyc2ajhp1|position|vvplay|vvad|220|setCurrentAudioTrack|audio_name|for|audio_set|getItem|last|open|controls|playbackRates|captions|rewind|icon|insertAfter||detach|ff00||button|getPosition|sec|png|player8|ff11|log|console|track_name|appendTo|play|click|no|scrolling|frameborder|file_code|src|top|zIndex|css|showCCform|data|1662367683|383371|dl|video_ad|doPlay|prevt|mp4|3E||jpg|thumbs|file|300|setTimeout|currentTrack|setItem|audioTrackChanged|dualSound|else|addClass|hasClass|toggleClass|Track|Audio|svg|dualy|images|mousedown|buttons|topbar|playAttemptFailed|beforePlay|Rewind|fr|Forward|ff|ready|set_audio_track|remove|this|upload_srt|prop|50px|margin|1000001|iframe|center|align|text|rgba|background|1000000|left|absolute|pause|setCurrentCaptions|Upload|contains|item|content|html|fviews|referer|prem|embed|3e57249ef633e0d03bf76ceb8d8a4b65|216|83|hash|view|get|TokenZir|window|hide|show|complete|slow|fadeIn|video_ad_fadein|time||cache|Cache|Content|headers|ajaxSetup|v2done|tott|vastdone2|vastdone1|vvbefore|playbackRateControls|cast|aboutlink|FileMoon|abouttext|UHD|1870|qualityLabels|sites|GNOME_POWER|link|2Fiframe|3C|allowfullscreen|22360|22640|22no|marginheight|marginwidth|2FGNOME_POWER|2F0fxcyc2ajhp1|2Fe|2Ffilemoon|2F|3A||22https|3Ciframe|code|sharing|fontOpacity|backgroundOpacity|Tahoma|fontFamily|303030|backgroundColor|FFFFFF|color|userFontScale|thumbnails|kind|0fxcyc2ajhp10000|url|get_slides|start|startparam|none|preload|html5|primary|hlshtml|androidhls|duration|uniform|stretching|0fxcyc2ajhp1_xt|image|2048|sp|6871|asn|127|srv|43200|_g3XlBcu2lmD9oDexD2NLWSmah2Nu3XcDrl93m9PwXY|m3u8||master|0fxcyc2ajhp1_x|00076|01|hls2|to|s01|delivery|storage|moon|sources|setup'''.split('|'))
 
 
 if __name__ == '__main__':
diff --git a/youtube_dl/jsinterp.py b/youtube_dl/jsinterp.py
index 02adf6678..799497acb 100644
--- a/youtube_dl/jsinterp.py
+++ b/youtube_dl/jsinterp.py
@@ -20,7 +20,9 @@ from .compat import (
     compat_basestring,
     compat_chr,
     compat_collections_chain_map as ChainMap,
+    compat_filter as filter,
     compat_itertools_zip_longest as zip_longest,
+    compat_map as map,
     compat_str,
 )
 
@@ -252,7 +254,7 @@ class Debugger(object):
                     cls.write('=> Raises:', e, '<-|', stmt, level=allow_recursion)
                 raise
             if cls.ENABLED and stmt.strip():
-                if should_ret or not repr(ret) == stmt:
+                if should_ret or repr(ret) != stmt:
                     cls.write(['->', '=>'][should_ret], repr(ret), '<-|', stmt, level=allow_recursion)
             return ret, should_ret
         return interpret_statement
@@ -365,6 +367,8 @@ class JSInterpreter(object):
         start, splits, pos, delim_len = 0, 0, 0, len(delim) - 1
         in_quote, escaping, after_op, in_regex_char_group = None, False, True, False
         skipping = 0
+        if skip_delims:
+            skip_delims = variadic(skip_delims)
         for idx, char in enumerate(expr):
             paren_delta = 0
             if not in_quote:
@@ -391,7 +395,7 @@ class JSInterpreter(object):
                 continue
             elif pos == 0 and skip_delims:
                 here = expr[idx:]
-                for s in variadic(skip_delims):
+                for s in skip_delims:
                     if here.startswith(s) and s:
                         skipping = len(s) - 1
                         break
@@ -412,7 +416,6 @@ class JSInterpreter(object):
         if delim is None:
             delim = expr and _MATCHING_PARENS[expr[0]]
         separated = list(cls._separate(expr, delim, 1))
-
         if len(separated) < 2:
             raise cls.Exception('No terminating paren {delim} in {expr!r:.5500}'.format(**locals()))
         return separated[0][1:].strip(), separated[1].strip()
@@ -487,6 +490,7 @@ class JSInterpreter(object):
         # fails on (eg) if (...) stmt1; else stmt2;
         sub_statements = list(self._separate(stmt, ';')) or ['']
         expr = stmt = sub_statements.pop().strip()
+
         for sub_stmt in sub_statements:
             ret, should_return = self.interpret_statement(sub_stmt, local_vars, allow_recursion)
             if should_return:
@@ -626,8 +630,7 @@ class JSInterpreter(object):
                     if m.group('err'):
                         catch_vars[m.group('err')] = err.error if isinstance(err, JS_Throw) else err
                     catch_vars = local_vars.new_child(m=catch_vars)
-                    err = None
-                    pending = self.interpret_statement(sub_expr, catch_vars, allow_recursion)
+                    err, pending = None, self.interpret_statement(sub_expr, catch_vars, allow_recursion)
 
             m = self._FINALLY_RE.match(expr)
             if m:
@@ -877,12 +880,12 @@ class JSInterpreter(object):
                     self.interpret_expression(v, local_vars, allow_recursion)
                     for v in self._separate(arg_str)]
 
-                if obj == compat_str:
+                if obj is compat_str:
                     if member == 'fromCharCode':
                         assertion(argvals, 'takes one or more arguments')
                         return ''.join(map(compat_chr, argvals))
                     raise self.Exception('Unsupported string method ' + member, expr=expr)
-                elif obj == float:
+                elif obj is float:
                     if member == 'pow':
                         assertion(len(argvals) == 2, 'takes two arguments')
                         return argvals[0] ** argvals[1]
@@ -907,12 +910,12 @@ class JSInterpreter(object):
                 elif member == 'splice':
                     assertion(isinstance(obj, list), 'must be applied on a list')
                     assertion(argvals, 'takes one or more arguments')
-                    index, howMany = map(int, (argvals + [len(obj)])[:2])
+                    index, how_many = map(int, (argvals + [len(obj)])[:2])
                     if index < 0:
                         index += len(obj)
                     add_items = argvals[2:]
                     res = []
-                    for i in range(index, min(index + howMany, len(obj))):
+                    for _ in range(index, min(index + how_many, len(obj))):
                         res.append(obj.pop(index))
                     for i, item in enumerate(add_items):
                         obj.insert(index + i, item)
@@ -1002,28 +1005,25 @@ class JSInterpreter(object):
     def extract_object(self, objname):
         _FUNC_NAME_RE = r'''(?:[a-zA-Z$0-9]+|"[a-zA-Z$0-9]+"|'[a-zA-Z$0-9]+')'''
         obj = {}
-        fields = None
-        for obj_m in re.finditer(
+        fields = next(filter(None, (
+            obj_m.group('fields') for obj_m in re.finditer(
                 r'''(?xs)
                     {0}\s*\.\s*{1}|{1}\s*=\s*\{{\s*
                         (?P<fields>({2}\s*:\s*function\s*\(.*?\)\s*\{{.*?}}(?:,\s*)?)*)
                     }}\s*;
                 '''.format(_NAME_RE, re.escape(objname), _FUNC_NAME_RE),
-                self.code):
-            fields = obj_m.group('fields')
-            if fields:
-                break
-        else:
+                self.code))), None)
+        if not fields:
             raise self.Exception('Could not find object ' + objname)
         # Currently, it only supports function definitions
-        fields_m = re.finditer(
-            r'''(?x)
-                (?P<key>%s)\s*:\s*function\s*\((?P<args>(?:%s|,)*)\){(?P<code>[^}]+)}
-            ''' % (_FUNC_NAME_RE, _NAME_RE),
-            fields)
-        for f in fields_m:
+        for f in re.finditer(
+                r'''(?x)
+                    (?P<key>%s)\s*:\s*function\s*\((?P<args>(?:%s|,)*)\){(?P<code>[^}]+)}
+                ''' % (_FUNC_NAME_RE, _NAME_RE),
+                fields):
             argnames = self.build_arglist(f.group('args'))
-            obj[remove_quotes(f.group('key'))] = self.build_function(argnames, f.group('code'))
+            name = remove_quotes(f.group('key'))
+            obj[name] = function_with_repr(self.build_function(argnames, f.group('code')), 'F<{0}>'.format(name))
 
         return obj
 
@@ -1058,7 +1058,7 @@ class JSInterpreter(object):
     def extract_function(self, funcname):
         return function_with_repr(
             self.extract_function_from_code(*self.extract_function_code(funcname)),
-            'F<%s>' % (funcname, ))
+            'F<%s>' % (funcname,))
 
     def extract_function_from_code(self, argnames, code, *global_stack):
         local_vars = {}
@@ -1067,7 +1067,7 @@ class JSInterpreter(object):
             if mobj is None:
                 break
             start, body_start = mobj.span()
-            body, remaining = self._separate_at_paren(code[body_start - 1:], '}')
+            body, remaining = self._separate_at_paren(code[body_start - 1:])
             name = self._named_object(local_vars, self.extract_function_from_code(
                 [x.strip() for x in mobj.group('args').split(',')],
                 body, local_vars, *global_stack))
@@ -1095,8 +1095,7 @@ class JSInterpreter(object):
         argnames = tuple(argnames)
 
         def resf(args, kwargs={}, allow_recursion=100):
-            global_stack[0].update(
-                zip_longest(argnames, args, fillvalue=None))
+            global_stack[0].update(zip_longest(argnames, args, fillvalue=None))
             global_stack[0].update(kwargs)
             var_stack = LocalNameSpace(*global_stack)
             ret, should_abort = self.interpret_statement(code.replace('\n', ' '), var_stack, allow_recursion - 1)