JsonForge · JSON errors
"undefined" is not valid JSON
The string "undefined" was passed to JSON.parse — typically from localStorage.getItem() on a missing key, or from JSON.stringify(undefined) which returns undefined rather than a string.
JSON has null but no undefined. Guard the read: JSON.parse(raw ?? "null").
The smallest input that causes it
undefined
JSON.parse on that gives, verbatim:
"undefined" is not valid JSON
The fix
{"value": null}That version parses.
Find it in your own document
Paste the JSON and get the error located by line and column, the document formatted, a schema inferred from it, and a diff against another version.
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