Null Undefined Booleans

Null: The value null represents the intentional absence of any object value. It is explicitly set by the programmer to indicate that there is no value. For example:
```
let x = null;
console.log(x); // null
```
Undefined: The value undefined is automatically assigned to variables that are declared but not initialized. For example:
```
let x;
console.log(x); // undefined
```
Booleans: The Booleans data type is used to represent truth values (true or false). They are typically used in conditions, loops, and other control structures to make decisions in your code. For example:
```
let x = true;
let y = false;
```

Difference between null and undefined When checking for null or undefined, beware of the differences between equality (==) and identity (===) operators, as the former performs type-conversion.

typeof null; // "object" (not "null" for legacy reasons)
typeof undefined; // "undefined"
null === undefined; // false
null == undefined; // true
null === null; // true
null == null; // true
!null; // true
Number.isNaN(1 + null); // false
Number.isNaN(1 + undefined); // true

Numbers Type Conversion