@angular-devkit/build-webpack

runWebpack: (
    config: webpack.Configuration,
    context: BuilderContext,
    options?: {
        logging?: WebpackLoggingCallback;
        webpackFactory?: WebpackFactory;
        shouldProvideStats?: boolean;
    }
) => Observable<any>;

runWebpackDevServer: (
    config: webpack.Configuration,
    context: BuilderContext,
    options?: {
        shouldProvideStats?: boolean;
        devServerConfig?: WebpackDevServer.Configuration;
        logging?: WebpackLoggingCallback;
        webpackFactory?: WebpackFactory;
        webpackDevServerFactory?: WebpackDevServerFactory;
    }
) => Observable<any>;

type BuildResult = BuilderOutput & {
    emittedFiles?: EmittedFiles[];
    webpackStats?: webpack.StatsCompilation;
    outputPath: string;
};

type DevServerBuildOutput = BuildResult & {
    port: number;
    family: string;
    address: string;
};

type WebpackBuilderSchema = RealWebpackBuilderSchema;

type WebpackDevServerFactory = typeof WebpackDevServer;