A concise comparison of NULL, undefined, and Nan

The null type also has only one value, which is null. Null is used to represent an object that does not already exist, and is commonly used to indicate that a function is attempting to return a nonexistent object.
The Undefined type has only one value, which is Undefined. When the declared variable has not been initialized, the default value for the variable is undefined.
NaN type represents non-numeric

Difference:
1, NULL is the reserved keyword of js, undefined and Nan are (Global object) a special property of window (the target in window is ture), not the keyword
2, typeof null is object,undefined for Undefined,nan, can be understood as NULL is a special object, Nan is a special number
3, participate in the numerical calculation: null value is 0 added to the calculation, undefined and Nan participate in the calculation results are Nan.
4, null==undefined, but not = = =;
5. The DOM tries to get the element that does not exist return null

A concise comparison of NULL, undefined, and Nan