1 2 3

{1: 1} {2: 2} {3: 3}

{ 1: undefined } undefined undefined

undefined undefined undefined

false true

true false

false false

true true

SyntaxError

ReferenceError

I love to program

undefined to program

${(x => x)('I love') to program

TypeError

Lydia

Sarah

undefined

ReferenceError

['🍕', '🍫', '🥑', '🍔']

['🍝', '🍫', '🥑', '🍔']

['🍝', '🍕', '🍫', '🥑', '🍔']

ReferenceError

true

false

undefined

TypeError

5

Promise {<pending>: 5}

Promise {<fulfilled>: 5}

Error

false null []

null "" true

{} "" []

null null true

["banana", "apple", "pear", "orange"]

[["banana", "apple"], "pear", "orange"]

["banana", "apple", ["pear"], "orange"]

SyntaxError

name Lydia age 21

["name", "Lydia"] ["age", 21]

["name", "age"] undefined

Error