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Javascript, the weirdo

· One min read
Matej Jelluš
Matej Jelluš
IT enthusiast that loves to write code and trying new things. Currently working in Bratislava as CTO in Kontentino.

Collection of JavaScript examples when it behaves...weird? Funny?

2 + true // => 3

0.1 + 0.2 // => 0.300000000000000004

typeof NaN // => number

'5' - 3 // => 2

'5' + 3 // => 53

'5' - '4' // => 1

'5' + + '5' // => 55

'foo' + + 'foo' // => fooNan

'5' + - '2' // => 5-2

'5' + - + - - + - - + + - + - + - + - - - '-2' // => 52

[] + [] // => ""

[] + {} // => [object Object]

{} + [] // => 0

[+!+[]]+[!+[]+!+[]]+[!+[]+!+[]+!+[]] // => "123"

null > 0 // => false
null == 0 // => false
null >= 0 // => true

parseInt(0.000001) // => 0
parseInt(0.0000001) // => 1

parseInt(0.000006) // => 0
parseInt(0.0000006) // => 6

Did you like this post? Was it helpful? I am always learning and trying new technologies. When I struggle with something and finally manage to solve it, I share my experience.