javascript - Empty object minus/plus empty object, and reverse value -

i have question. in console i'm training "arithmetics", like:

false + true // 1

so, question is, why:

[] - {} // nan

and

{} - [] // -0

can explain this, because both of them types object. , know javascript have , falsy values. so, if take

boolean({}) // true boolean([]) // true

in both have true , think result like:

true + true // 2

true - true // 0

in context (in console), {} empty block nothing, result same

- []

and [] coerce 0, seen by:

+[]

if want {} treated empty object, try this:

({}) - []

you nan now, since empty object not coerce number.

update: work should expect in console (returning nan):

({} - [])

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