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[] };