Confusing operator

Arithmetic operators: 

the console.log (undefined + NaN3) // NaN3 
the console.log (+ undefined null) // NaN3 
the console.log (+ undefined null) // NaN3 
the console.log (+ NaN3 null) // NaN3 
Console. log (. 1 + null) // A
 to true equivalent. 1; 
to false and a null is equivalent to 0; 
the console.log ( ". 1" + null ) 1null 
1+ {name: "ADMIN"} // [Object Object] 
1+ [ 3,4,5,6] // 13,4,5,6 

conclusion: as long as the string concatenation, will become the string. NaN3 is added to the special value. As the character arrays together. 

Logical Operators&&:

console.log(undefined&&NaN) //u
console.log(undefined&&null) //u
console.log(null&&undefined) //n
console.log(NaN&&null) //n
console.log(1&&null) //null
console.log("1"&&null) //null

Conclusion: The special value && special value, who wrote the previous results is who. Null any phase value results are null (except special value). And false && think, are false; 0 and phase were 0; 
0 and 0 false phase; and a digital phase 1;