mirror of
https://github.com/chubin/cheat.sheets
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50 lines
1.0 KiB
Plaintext
50 lines
1.0 KiB
Plaintext
// Nothing is weird here, if you think a little bit more about it
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// but it seems to be
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// Null is an Object
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typeof null // => 'object'
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// Weird decimal calculation
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0.1 + 0.2 // -> 0.30000000000000004
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// Despite this, null is not an instance of an Object
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null instanceof Object // => false
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// "string" is not an instance of String
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"string" instanceof String
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// NaN is a number
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typeof NaN // -> 'Number'
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// NaN is not considered equal to itself
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NaN === NaN // -> false
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// Array With No Keys == False
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new Array() == false // -> true
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// big integer numbers
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9999999999999999 // -> 10000000000000000
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//
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[]+[] // -> ""
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[]+{} // -> "[object Object]"
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{}+[] // -> "{}+[]"
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{}+{} // -> NaN
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// Comparisons
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3>2>1 // -> false
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// Boolean arithmetic
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true+true===2 // -> true
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true-true===0 // -> true
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true===1 // -> false
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// Something really strange
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(!+[]+[]+![]).length // -> 9
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// because:
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// +[] -> 0
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// !+[] -> true
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// !+[]+[] -> 'true'
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// etc.
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