import { Script } from 'vm';
import { Transform } from 'stream';
export interface VMContext {
    $in?: any;
    $out?: any;
}
/**
code: string
  Two important facts about this code:
  1. It should process a global variable, `$in`, which represents the
     current object in the stream.
  2. It should set the global variable `$out`, which represents the
     object that will be returned and sent downstream.
context?: any = {}
  Results and side effects are tracked in this global context object.
filename?: string = 'streaming.vm'
  Used in stack traces.
*/
export declare class VM<S, T> extends Transform {
    context: VMContext;
    filename: string;
    protected script: Script;
    constructor(code: string, context?: VMContext, filename?: string);
    /**
    each chunk should be a discrete object
    encoding should be null
    */
    _transform(chunk: S, encoding: BufferEncoding, callback: (error?: Error, outputChunk?: T) => void): void;
    /**
    Run a bit of code once using the streaming.VM's global context.
    */
    run(code: string): any;
}