[] is an empty array ![] is treated as false combining a boolean with the empty array returns "false" as a string (so true + [] = "true", false + [] = "false") ! + [] is treated as true ! + [] + ! + [] is treated as 2 since true + true = 1 + 1 = 2 so you have "false"[2], which is l for the o it's [] is an empty array [] + {} returns "[object Object]" as a string ({} + [] returns 0) ![] is false !![] is true +!![] casts it to an integer so that part is "[object Object]"[1], which returns "o"

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[–] elvith@feddit.de 7 points 1 year ago (1 children)

There's a nice presentation that explains this behaviour quite understandable: https://youtu.be/sRWE5tnaxlI

[–] PipedLinkBot@feddit.rocks 7 points 1 year ago

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