declare module "polyfill-library" {
	import {Readable} from 'stream';

	function listAllPolyfills(): string[];
	function describePolyfill(featureName: string): Promise<PolyfillMetadata|undefined>;
	function getOptions(opts: Partial<PolyfillOptions>): PolyfillOptions;
	function getPolyfills(opts: Partial<PolyfillOptions>): Promise<PolyfillFeatures>;
	function getPolyfillString(opts: Partial<PolyfillOptions>&{stream?: true}): Readable;
	function getPolyfillString(opts: Partial<PolyfillOptions>&{stream: false}): Promise<string>;

	type PolyfillMetadata = {

	};

	type PolyfillFeatureList = {
		[featureName: string]: {
			flags?: string[]
		}
	};

	type PolyfillOptions = {
		minify: boolean,
		unknown: 'polyfill'|'ignore',
		features: PolyfillFeatureList,
		excludes: string[],
		uaString: string,
		rum: boolean,
	};

	type PolyfillFeature = {
		flags: string[],
		dependencyOf: string[],
		aliasOf: string[],
	}

	type PolyfillFeatures = { [featureName: string]: PolyfillFeature };
}