Null, Undefined and Symbol

Learn about the Null, Undefined and Symbol primitive datatypes

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Null, undefined, and Symbols are primitive types.


Null represents an intentional absence of a primitive or composite value of a defined variable.


Undefined represents that a value is not defined.


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.

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