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NULL VS UNDEFINED



NULL VS UNDEFINED

       Undefined means a variable has been declared but has not yet been assigned a value. On the other hand, null is an assignment value. It can be assigned to a variable as a representation of no value. Also, undefined and null both are two different data types:

undefined is a type itself (undefined)
null is an object.


var a;//undefined

var b = null;

var c=5;

var d = a+c // NaN

var e = b+c  //5

 

If  I am trying to do any mathematical  operation with null and number it gives me some  number as output,  instead of null if i am doing it with undefined and number the result is NaN
null !== 0;  
undefined !==0;


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