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obj               type      def emp con pro pcon ccl pcl
----------------- --------- --- --- --- --- ---- --- ---
undef             undefined  NO YES  NO  NO   NO  NO  NO
null              object     NO YES  NO  NO   NO  NO  NO
true              boolean   YES  NO YES  NO   NO  NO  NO
false             boolean   YES  NO YES  NO   NO  NO  NO
{}                object    YES YES YES  NO   NO  NO  NO
[]                object    YES YES YES  NO   NO  NO  NO
{a:1}             object    YES  NO YES  NO   NO  NO  NO
[1,2]             object    YES  NO YES  NO   NO  NO  NO
NewClass          function  YES  NO YES YES  YES  NO  NO
new NewClass()    object    YES  NO YES  NO   NO  NO  NO
42                number    YES  NO YES  NO   NO  NO  NO
3.14              number    YES  NO YES  NO   NO  NO  NO
new Number(42)    object    YES YES YES  NO   NO  NO  NO
BigInt(42)        bigint    YES  NO YES  NO   NO  NO  NO
'abc'             string    YES  NO YES  NO   NO  NO  NO
new String('abc') object    YES  NO YES  NO   NO  NO  NO
() -> return 3    function  YES  NO YES YES  YES  NO  NO
() => return 3    function  YES  NO YES  NO   NO  NO  NO