Jint

Working with values ​

Jint represents JavaScript values with JsValue. Inspect the type before using a typed accessor:

csharp
JsValue value = new Engine().Evaluate("({ name: 'Ada', score: 9.5 })");

if (value.IsObject())
{
    var obj = value.AsObject();
    Console.WriteLine(obj.Get("name").AsString());
    Console.WriteLine(obj.Get("score").AsNumber());
}

Common predicates include IsUndefined, IsNull, IsString, IsNumber, IsBoolean, IsBigInt, IsSymbol, IsObject, IsArray, IsDate, IsPromise, and IsCallable. Typed accessors such as AsString, AsNumber, AsBoolean, AsObject, and AsArray throw when the value has the wrong type.

CLR conversion ​

JsValue.FromObject projects a CLR value into an engine. ToObject converts ordinary JavaScript values to CLR primitives, arrays, and dictionaries:

csharp
var engine = new Engine();
var jsValue = JsValue.FromObject(engine, new[] { 1, 2, 3 });
var clrValue = engine.Evaluate("({ ok: true, items: [1, 2] })").ToObject();

For untrusted or externally returned results, prefer Engine.ConvertResult. It creates a detached CLR graph and can enforce ResultLimits while traversing:

csharp
var engine = new Engine(options =>
    options.ResultLimits = ResultLimits.Conservative);

var detached = engine.ConvertResult(engine.Evaluate("({ value: 'ok' })"));

Cycles, functions, and symbols cannot be detached this way. A wrapped CLR object is already host-owned, so conversion returns its target rather than walking its graph.

Engine affinity ​

Do not pass a JsValue object from one engine to another. A JavaScript object retains its creating engine and realm, and cross-engine use is unsupported and not validated. Share Prepared<Script>, Prepared<Module>, or plain CLR data instead.

CLR arrays are copied to independent native JavaScript arrays by default. See CLR interop for live views and write permissions.