Why is null an object and what's the difference between null and undefined?

Question

Why is null considered an object in JavaScript?

Is checking

if ( object == null )
      Do something

the

Answer 1

Some precisions:

null and undefined are two different values. One is representing the absence of a value for a name and the other is representing the absence of a name.

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What happens in an if goes as follows for if( o ):

The expression in the parentheses o is evaluated, and then the if kicks in type-coercing the value of the expression in the parentheses - in our case o.

Falsy (that will get coerced to false) values in JavaScript are: '', null, undefined, 0, and false.