concat test#1
get trap: concat
get trap: constructor
get trap: length
concat test#2
get trap: concat
get trap: constructor
get trap: length
has trap: 0
get trap: 0
has trap: 1
get trap: 1
has trap: 2
get trap: 2
has trap: 3
get trap: 3
unshift  test
get trap: unshift
get trap: length
splice test
get trap: splice
get trap: length
get trap: constructor
has trap: 0
get trap: 0
has trap: 1
get trap: 1
has trap: 2
get trap: 2
has trap: 3
get trap: 3
delete trap: 3
delete trap: 2