TRUTHY TOOLS

Empty vs Null vs Undefined

A simple reference table for common empty, blank, missing, and empty-like values.

Empty does not always mean missing. Values like 0 and false are real values, while null, undefined, and missing keys usually mean absent or unavailable data.
Value Type Context Example
null Explicit empty value A deliberate absence of a value. Common in JSON, APIs, databases, and programming languages. {"name": null}
undefined Not assigned A value has not been assigned or does not exist. Common in JavaScript. let value;
"" Empty string A string exists, but it contains no characters. {"name": ""}
[] Empty array A list exists, but it contains no items. {"items": []}
{} Empty object An object exists, but it contains no properties. {"data": {}}
0 Zero A real numeric value. It is empty-like in some loose checks, but it is not missing. {"count": 0}
false Boolean false A real boolean value. It is empty-like in some loose checks, but it is not missing. {"active": false}
NaN Invalid number Means Not-a-Number. Usually appears when a numeric calculation or parse fails. Number("abc")
Whitespace Blank-looking string A string with spaces, tabs, or line breaks. It may look empty but still contains characters. " "
Missing key Absent field The field does not exist at all. Different from a field that exists with null or empty string. {"email": "a@example.com"}
Useful for APIs, automations, JSON payloads, form submissions, databases, and code checks where blank-looking values can behave differently.

About this tool

Empty Values helps developers, QA engineers, technical writers, and support teams reference table for common empty, blank, missing, and empty-like values. Use it during debugging sessions, documentation updates, code reviews, and integration tests when you need a focused result you can read, copy, or share without opening a heavier application.

Use cases

  • Use Empty Values during debugging when you need to reference table for common empty, blank, missing, and empty-like values without leaving the browser.
  • Copy Empty Values output into tickets, docs, test notes, spreadsheets, or chat threads so teammates can verify the same result.
  • Keep Empty Values open as a repeatable browser utility for quick checks instead of building a one-off spreadsheet or script.

FAQ

What is Empty Values best used for?

Empty Values is best used when you need to reference table for common empty, blank, missing, and empty-like values in a fast, copy-friendly browser workflow.

Who benefits most from the Empty Values tool?

It is especially helpful for developers, QA engineers, technical writers, and support teams who handle debugging sessions, documentation updates, code reviews, and integration tests, and need clear output without extra setup.

Can I use Empty Values results in documentation or bug reports?

Yes. The output is designed to be readable and easy to paste into issues, docs, QA notes, or team conversations.