@types/pump/index.d.ts

/// <reference types="node" />

declare function pump(streams: pump.Stream[], callback?: pump.Callback): pump.Stream;

// callback have to be passed as last argument
declare function pump(...streams: Array<pump.Stream | pump.Callback>): pump.Stream;

declare namespace pump {
    type Callback = (err?: Error) => any;
    type Stream = NodeJS.ReadableStream | NodeJS.WritableStream;
}

export = pump;