What’s the difference between undeclared, undefined and null in JavaScript?

JavaScript has three different empty states for variables. Learn their differences and how you can check for each one.


This content originally appeared on 30 seconds of code and was authored by 30 seconds of code

JavaScript has three different empty states for variables. Learn their differences and how you can check for each one.


This content originally appeared on 30 seconds of code and was authored by 30 seconds of code


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30 seconds of code | Sciencx (2021-03-29T09:00:00+00:00) What’s the difference between undeclared, undefined and null in JavaScript?. Retrieved from https://www.scien.cx/2021/03/29/whats-the-difference-between-undeclared-undefined-and-null-in-javascript/

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IEEE
" » What’s the difference between undeclared, undefined and null in JavaScript?." 30 seconds of code | Sciencx [Online]. Available: https://www.scien.cx/2021/03/29/whats-the-difference-between-undeclared-undefined-and-null-in-javascript/. [Accessed: ]
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» What’s the difference between undeclared, undefined and null in JavaScript? | 30 seconds of code | Sciencx | https://www.scien.cx/2021/03/29/whats-the-difference-between-undeclared-undefined-and-null-in-javascript/ |

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