Jint & JSONata

[Neil-Craig-Nintex]

I've been trying to use JSONata to transform some JSON documents in an old .NET Framework application. Since there is no suitable .NET native JSONata library available, I'm using Jint to perform the transformation using the JS library.
It works well enough, but recursion & looping have a tendency to cause Stack Overflow exceptions. The weird thing is that the JSONata Exerciser works fine, just not Jint.

Here is an example of the implementation:

try
{
    // Load the jsonata library
    string jsonata_js = File.ReadAllText(RESOURCE_PATH);

    m_engine = new Engine()
        .Execute(jsonata_js)
        .Execute(@"
            async function evaluateJsonata(query, jsondata) {
                const result = await jsonata(query).evaluate(JSON.parse(jsondata));
                return result;
            }
        ");

    // Evaluate the expression
    var result = m_engine.Invoke("evaluateJsonata", query, jsonData).UnwrapIfPromise();
}
catch (JintException ex)
{
    throw new Exception($"Error evaluating JSONata expression: {ex.Message}");
}
catch (Exception ex)
{
    throw new Exception($"Error executing Jsonata query: {ex.Message}");
}

The StackOverflow exception occurs on the 'Invoke' line....

Has anyone tried something similar, and perhaps can share some pointers?

Thanks in advance

[lahma]

Can you share minimal sample code which shows the problem?

[Neil-Craig-Nintex]

Hi Marko, edited the post with an example

[lahma]

With given example url and query doesn't repro, but you could try new Engine(options => options.Constraints.MaxExecutionStackCount = int.MaxValue)

[Neil-Craig-Nintex]

Thanks Marko, that did the trick. I'm however still concerned with the difference in performance between the JSONata Exerciser and my .NET Framework implementation.

[lahma]

If you could anonymize the data or create same shape of data with used query it would make investigation easier. Jint is an Interpreter and will always be slower than Node for CPU intensive tasks.

[sebastienros]

My thoughts:

In the case of JSONata Exerciser I assume since it's a web app it's running the script directly in V8 (if you are using Chrome or Edge) so it's compiled.

Now time for some sarcasm, someone should rewrite JSONata in GO and it would be 10x faster.

Less sarcasm, here is a set of very useful dotnet libraries to manage JSON data: https://github.com/json-everything/json-everything?tab=readme-ov-file
For instance one implements JSONPath, and combined with some JavaScript (jint?) it could provide a good substitute.
If you want to have fun you could even try to convert JSONata directly to C#, chatgpt could be very useful for that.

[Neil-Craig-Nintex]

@lahma & @sebastienros - I will try to get an anonymized example on here. I have no doubt that I'm doing something wrong, as the performance differs from 17-100ms on https://www.jsonatastudio.com/playground/, to my .NET framework implementation which does the same job but in 30-37 seconds. I hope to learn a lot from this experience as I have more plans for Jint in other projects. Thanks for your interest and help.