'key’

{ ‘key’ }

{ Symbol: ‘key’}

undefined

error

[1,2,3,[1,2,3,4,2,3,4]]

[1,2,3,1,2,3,4,2,3,4]

[1,2,3,[1,2,3,4, [2,3,4]]]

undefined

TypeError

undefined

false

true

TypeError

SyntaxError

[ "name", "Artur" ] [ "age", 36 ]

"name" "Artur" "age" 36

[ "name", "Artur" ] undefined

TypeError

"Mercedes"

TypeError

undefined

"Audi"

SyntaxError

function

[1]

TypeError

SyntaxError

undefined

[1, [2, 3, 4]]

[1, 2, 3, 4]

[[1, 2, 3, 4]]

[[1, [2, 3, 4]]]

Error

55

10

10 55

SyntaxError

Undefined

"global" "outer-2" "inner"

"global" "outer" "inner"

"guess" "outer" "inner"

"guess" "outer-2" "inner"

Error

Error

false

1

true

undefined