Json Patch Tester

Applies a JSON Patch (RFC 6902) array to a target JSON document and shows the resulting document. It supports the six standard operations — add, remove, replace, move, copy, and test — including the - sentinel for appending to arrays. Errors such as invalid JSON, missing paths, or failed test ops are surfaced inline.

1. Paste the target JSON document into the Target Document card 2. Paste the JSON Patch array into the Patch Document card (each item needs op and path; add/replace/test need value; move/copy need from) 3. Click Apply Patch to run operations sequentially on a deep clone of the target 4. Review the Result card, or the red error banner if a patch fails 5. Use Load Example to populate both fields with a sample document and patch

Paths use RFC 6906 JSON Pointer syntax: /address/city, /hobbies/0, etc. add with path ending in /- appends to an array; numeric indices splice into arrays; object keys are created if missing. test compares the value at path with the supplied value using JSON.stringify equality and aborts the whole patch on mismatch. The implementation is hand-rolled, so some edge cases (nested array moves, escaping ~/ in keys) may not match a strictly conformant library.