Null, undefined, and Symbols are primitive types.
Null
Null represents an intentional absence of a primitive or composite value of a defined variable.
Undefined
Undefined represents that a value is not defined.
Symbol
A Symbol()
is a unique value without an associated literal value. They are useful as unique keys, because Symbol() == Symbol()
is false. At this stage, just accept that symbols exist. You don’t have to use them for anything yet.
Get hands-on with 1200+ tech skills courses.