! + 1 / / false
what is the principle
+ and ! are unary operators. First + gets 1 and then ! gets false you can refer to the operator priority problem. Logic does not take a value that is originally true as false
for ! + 1 , where + is here as the unary plus sign (+) , calculates the value of the following Operand, and attempts to convert it to a numeric value. For example, + 1 = > 1 , +'1' = > 1 . Logic is not! only determines whether the subsequent Operand is true. The false values of are: null,undefined,false,NaN,0,-0,+0 . The priority of
unary addition is 16, and the priority of logical non is 16, but their relevance is from right to left, so here + 1 is true , and logical non! is followed by false .
refer to priority summary
Logic in mathematics. Not only! + 1, any string you can get is false. ! 0 = true,! 1 = false
must be false!
is equivalent to! (1), of course it is false
! Is to reverse the Boolean value
! ture==false
! false==true
Boolean (1) = true
Boolean (+ 1) = true
! true is naturally equal to false
false
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