export function lookup(filenameOrExt: string): string | false;
export function contentType(filenameOrExt: string): string | false;
export function extension(typeString: string): string | false;
export function charset(typeString: string): string | false;
export namespace charsets {
    const lookup: typeof charset;
}
export const types: { [key: string]: string };
export const extensions: { [key: string]: string[] };