==3822== Conditional jump or move depends on uninitialised value(s)
==3822==    at 0x484F238: strlen (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==3822==    by 0x157E0B: js_atom_concat_str (quickjs.c:3503)
==3822==    by 0x1966DF: js_atom_concat_num (quickjs.c:3525)
==3822==    by 0x1966DF: js_parse_class (quickjs.c:23350)
==3822==    by 0x189CB9: js_parse_postfix_expr (quickjs.c:24653)
==3822==    by 0x18C15C: js_parse_unary (quickjs.c:25373)
==3822==    by 0x18C84D: js_parse_expr_binary (quickjs.c:25439)
==3822==    by 0x18C84D: js_parse_expr_binary (quickjs.c:25439)
==3822==    by 0x18C84D: js_parse_expr_binary (quickjs.c:25439)
==3822==    by 0x18C84D: js_parse_expr_binary (quickjs.c:25439)
==3822==    by 0x18C84D: js_parse_expr_binary (quickjs.c:25439)
==3822==    by 0x18C84D: js_parse_expr_binary (quickjs.c:25439)
==3822==    by 0x18C84D: js_parse_expr_binary (quickjs.c:25439)
==3822==  Uninitialised value was created by a stack allocation
==3822==    at 0x196400: js_parse_class (quickjs.c:23081)