possible characters: abcdefijlnorstuy NOI []
sample string:       obfuscated

undefined        = ([][{}]+[])
[object Object]  = ({}+[])
false            = (!{}+[])
true             = ([]+!!{})
NaN              = ({}-{}+[])
Infinity         = (!!{}/![]+[])

0 = !{}+![]
0 = +!{}
1 = !!{}+![]
1 = +!![]
1 = +!+{}
2 = ![]+!!{}+!![]
2 = !!{}+!![]
2 = +!+[]+!!{}
3 = ![]+!!{}+!!{}+!![]
5 = (!!{}+!![])*(![]+!!{}+!![])+!!{}


o ([]+{}+[])[1]
b ([]+{}+[])[2]
f (!{}+[])[0]
u ([][{}]+[])[0]
s (!{}+[])[3]
c ({}+{})[5]
a ({}-{}+[])[1]
t ([]+!!{})[0]
e ([]+!!{})[3]
d ([][{}]+[])[2]


([]+{}+[])[!!{}+![]]+
([]+{}+[])[!!{}+!![]]+
(!{}+[])[!{}+![]]+
([][{}]+[])[!{}+![]]+
(!{}+[])[![]+!!{}+!!{}+!![]]+
({}+{})[(!!{}+!![])*(!!{}+!![])+!!{}]+
({}-{}+[])[!!{}+![]]+
([]+!!{})[!{}+![]]+
([]+!!{})[![]+!!{}+!!{}+!![]]+
([][{}]+[])[![]+!!{}+!![]]

([]+{}+[])[!!{}+![]]+([]+{}+[])[!!{}+!![]]+(!{}+[])[!{}+![]]+([][{}]+[])[!{}+![]]+(!{}+[])[![]+!!{}+!!{}+!![]]+({}+{})[(!!{}+!![])*(!!{}+!![])+!!{}]+({}-{}+[])[!!{}+![]]+([]+!!{})[!{}+![]]+([]+!!{})[![]+!!{}+!!{}+!![]]+([][{}]+[])[![]+!!{}+!![]]