The typeof operator allows us to see which type is stored in a variable.
  • null for unknown values 
  • undefined for unassigned values
The assignment operator "=" returns a value
That’s obvious for most of them like addition + or multiplication *. But the assignment operator follows this rule too.

The call x = value writes the value into x and then returns it.

Operator Precedence: 
  1. (), 
  2. unary (+, -, ++, --), 
  3. multiply/devide, 
  4. plus/minus, 
  5. assignment
An operator always returns a value.
A strict equality operator === checks the equality without type conversion.
In other words, if a and b are of different types, then a === b immediately returns false without an attempt to convert them.

Values null and undefined are special: 
  • they equal == each other and don’t equal anything else.
  • null === undefined // returns false