Jint

Node compatibility ​

Jint implements ECMAScript, not the complete Node.js runtime. Its Node compatibility features are narrow, explicit opt-ins.

process ​

csharp
var engine = new Engine(options => options.UseNodeProcess(process =>
{
    process.EnvironmentVariableAllowlist = ["NODE_ENV"];
    process.EnvironmentOverrides = new Dictionary<string, string>
    {
        ["NODE_ENV"] = "production"
    };
}));

var mode = engine.Evaluate("process.env.NODE_ENV").AsString();

No environment variable is visible until allowlisted. process.env is materialized once and script writes remain local. cwd() returns the configured WorkingDirectory ("/" by default), never the host process's real directory. argv is empty, while exit, abort, kill, and chdir are absent.

process.nextTick uses Jint's single job queue, so it and promise reactions run in registration order rather than Node's separate next-tick ordering.

Package resolution and built-ins ​

Use NodeStyleModuleLoader for an on-disk node_modules tree:

csharp
var engine = new Engine(options => options
    .UseModules(new NodeStyleModuleLoader("/app"))
    .UseNodeBuiltinModules());

The base path bounds both reachable files and the upward package search. Built-ins are limited to pure utility modules:

  • node:path, node:path/posix, and node:path/win32
  • node:querystring
  • node:url

Unprefixed path, querystring, and url work by default. A host-registered module with the same name wins. Resource-bearing modules such as node:fs, node:child_process, node:http, node:crypto, node:os, and node:buffer are deliberately absent.

node:path is available on all Jint target frameworks. node:url and node:querystring require .NET 8 because they use Jint's WHATWG URL implementation.

See Modules for general module loading and graph policy.