The library can fix the following issues:

• Add missing quotes around keys
• Add missing escape characters
• Add missing commas
• Add missing closing brackets
• Replace single quotes with double quotes
• Replace special quote characters like “...” with regular double quotes
• Replace special white space characters with regular spaces
• Replace Python constants None, True, and False with null, true, and false
• Strip trailing commas
• Strip comments like /* ... */ and // ...
• Strip JSONP notation like callback({ ... })
• Strip escape characters from an escaped string like {\"stringified\": \"content\"}
• Strip MongoDB data types like NumberLong(2) and ISODate("2012-12-19T06:01:17.171Z")
• Concatenate strings like "long text" + "more text on next line"
• Turn newline delimited JSON into a valid JSON array, for example:

  { "id": 1, "name": "John" }
  { "id": 2, "name": "Sarah" }
  

In LLM mode

• Strip characters heading the JSON opening brace and trailing the JSON closing brace.

Use

Use the original typescript version in a full-fledged application: https://jsoneditoronline.org Read the background article "How to fix JSON and validate it with ease"

Here's the updated code example that reflects the changes made in your fork:

Code Example (Updated in Fork)

In this fork, the RepairJson method has been updated to remove static properties, making it thread-safe. The method now accepts parameters instead of relying on global settings.

Before (Original Code)

// Enable throwing exceptions when JSON code can not be repaired or even understood (enabled by default)
JsonRepair.ThrowExceptions = true;

// Set context as LLM or Other. This will repair the json slightly differently. (Other by default)
JsonRepair.Context = Other;

try
{
    string json = "{name: 'John'}";
    string repaired = JsonRepair.JsonRepair(json);
    Console.WriteLine(repaired);
    // Output: {"name": "John"}
}
catch (JSONRepairError err)
{
    Console.WriteLine(err.Message);
    Console.WriteLine("Position: " + err.Data["Position"]);
}

Now (Updated in Fork)

try
{
    // The following is invalid JSON: it consists of JSON contents copied from 
    // a JavaScript code base, where the keys are missing double quotes, 
    // and strings are using single quotes:
    string json = "{name: 'John'}";

    // New method signature using parameters instead of static properties
    string repaired = JsonRepair.RepairJson(json, InputType.Other, true);
    
    Console.WriteLine(repaired);
    // Output: {"name": "John"}
}
catch (JSONRepairError err)
{
    Console.WriteLine(err.Message);
    Console.WriteLine("Position: " + err.Data["Position"]);
}

What Changed?

• RepairJson now takes parameters (inputType and throwsException) instead of relying on static properties.
• The class is now thread-safe because no shared state (ThrowExceptions, Context) is used.
• The method call is explicit and does not require setting global configuration.

This change improves maintainability and makes the library safe for concurrent execution in multi-threaded environments.

Command Line Interface (CLI)

The github archive comes with a jsonrepair cli tool, it can be used on the command line. To use, build JsonRepair-CLI.

Usage:

$ jsonrepair "inputfilename.json" {OPTIONS}

Options:

--version,   -v                       Show application version
--help,      -h                       Show help
--new,       -n "outputfilename.json" Write to new file
--overwrite, -o                       Replace the input file
--llm,       -l                       Parse in LLM mode

Example usage:

$ jsonrepair "broken.json"                         # Repair a file, output to console
$ jsonrepair "broken.json" > "repaired.json"       # Repair a file, output to command line and pipe to file
$ jsonrepair "broken.json" -n -l "repaired.json"   # Repair a file in LLM mode, output to command line and pipe to file
$ jsonrepair "broken.json" --overwrite             # Repair a file, replace the input json file

GUI

The archive also comes with a minimal GUI that shows a somewhat simplistic diff between the original and fixed JSON This GUI heavily leans on the awesome FastColoredTextBox library and the the diff sample in particular.

Alternatives:

Similar libraries:

• https://github.com/josdejong/jsonrepair
• https://github.com/RyanMarcus/dirty-json

Acknowledgements

Thanks go out to Jos de Jong, who not only did all the heavy lifting in the original jsonrepair for typescript library, but also patiently helped getting this port to pass all unit tests.

License

Released under the MITS license.