[jsinterp] Handle negative numbers better

Closes #6131

test/test_jsinterp.py

@@ -445,6 +445,22 @@ class TestJSInterpreter(unittest.TestCase):
         jsi = JSInterpreter('function x(){return 1236566549 << 5}')
         self.assertEqual(jsi.call_function('x'), 915423904)
 
+    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)
+
 
 if __name__ == '__main__':
     unittest.main()

test/test_youtube_signature.py

@@ -142,6 +142,10 @@ _NSIG_TESTS = [
         'https://www.youtube.com/s/player/dac945fd/player_ias.vflset/en_US/base.js',
         'o8BkRxXhuYsBCWi6RplPdP', '3Lx32v_hmzTm6A',
     ),
+    (
+        'https://www.youtube.com/s/player/6f20102c/player_ias.vflset/en_US/base.js',
+        'lE8DhoDmKqnmJJ', 'pJTTX6XyJP2BYw',
+    ),
 ]
 
 

yt_dlp/jsinterp.py

@@ -243,7 +243,7 @@ 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 = None, False, True, False
+        in_quote, escaping, after_op, in_regex_char_group, in_unary_op = None, False, True, False, False
         for idx, char in enumerate(expr):
             if not in_quote and char in _MATCHING_PARENS:
                 counters[_MATCHING_PARENS[char]] += 1
@@ -258,9 +258,11 @@ class JSInterpreter:
                 elif in_quote == '/' and char in '[]':
                     in_regex_char_group = char == '['
             escaping = not escaping and in_quote and char == '\\'
-            after_op = not in_quote and char in OP_CHARS or (char.isspace() and after_op)
+            in_unary_op = (not in_quote and not in_regex_char_group
+                           and after_op not in (True, False) and char in '-+')
+            after_op = char if (not in_quote and char in OP_CHARS) else (char.isspace() and after_op)
 
-            if char != delim[pos] or any(counters.values()) or in_quote:
+            if char != delim[pos] or any(counters.values()) or in_quote or in_unary_op:
                 pos = 0
                 continue
             elif pos != delim_len: