diff --git a/index.d.ts b/index.d.ts
index 58dc9e1de..c0138bea9 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -8,683 +8,729 @@ export type RNFetchBlob = RNFetchBlobStatic;
 export default RNFetchBlob;
 
 interface RNFetchBlobStatic {
-    fetch(method: Methods, url: string, headers?: { [key: string]: string }, body?: any
-        | null): StatefulPromise<FetchBlobResponse>;
-    base64: { encode(input: string): string; decode(input: string): string };
-    android: AndroidApi;
-    ios: IOSApi;
-    config(options: RNFetchBlobConfig): RNFetchBlobStatic;
-    session(name: string): RNFetchBlobSession;
-    fs: FS;
-    wrap(path: string): string;
-    net: Net;
-    polyfill: Polyfill;
-    // this require external module https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/oboe
-    JSONStream: any;
+  fetch(
+    method: Methods,
+    url: string,
+    headers?: { [key: string]: string },
+    body?: any | null
+  ): StatefulPromise<FetchBlobResponse>;
+  base64: { encode(input: string): string; decode(input: string): string };
+  android: AndroidApi;
+  ios: IOSApi;
+  config(options: RNFetchBlobConfig): RNFetchBlobStatic;
+  session(name: string): RNFetchBlobSession;
+  fs: FS;
+  wrap(path: string): string;
+  net: Net;
+  polyfill: Polyfill;
+  // this require external module https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/oboe
+  JSONStream: any;
 }
 
 export interface Polyfill {
-    Blob: PolyfillBlob;
-    File: PolyfillFile;
-    XMLHttpRequest: PolyfillXMLHttpRequest;
-    ProgressEvent: PolyfillProgressEvent;
-    Event: PolyfillEvent;
-    FileReader: PolyfillFileReader;
-    Fetch: PolyfillFetch;
+  Blob: PolyfillBlob;
+  File: PolyfillFile;
+  XMLHttpRequest: PolyfillXMLHttpRequest;
+  ProgressEvent: PolyfillProgressEvent;
+  Event: PolyfillEvent;
+  FileReader: PolyfillFileReader;
+  Fetch: PolyfillFetch;
 }
 
 export declare class PolyfillFetch extends RNFetchBlobFetchPolyfill {
-    constructor(config: RNFetchBlobConfig);
+  constructor(config: RNFetchBlobConfig);
 }
 
 export declare class RNFetchBlobFetchPolyfill {
-    constructor(config: RNFetchBlobConfig);
+  constructor(config: RNFetchBlobConfig);
 
-    build(): (url: string, options: RNFetchBlobConfig) => StatefulPromise<RNFetchBlobFetchRepsonse>;
+  build(): (
+    url: string,
+    options: RNFetchBlobConfig
+  ) => StatefulPromise<RNFetchBlobFetchRepsonse>;
 }
 
 export interface RNFetchBlobFetchRepsonse {
-    arrayBuffer(): Promise<any[]>;
-    blob(): Promise<PolyfillBlob>;
-    json(): Promise<any>;
-    rawResp(): Promise<FetchBlobResponse>;
-    text(): Promise<string>;
-    bodyUsed: boolean;
-    headers: any;
-    ok: boolean;
-    resp: FetchBlobResponse;
-    rnfbResp: FetchBlobResponse;
-    rnfbRespInfo: RNFetchBlobResponseInfo;
-    status: number;
-    type: string;
+  arrayBuffer(): Promise<any[]>;
+  blob(): Promise<PolyfillBlob>;
+  json(): Promise<any>;
+  rawResp(): Promise<FetchBlobResponse>;
+  text(): Promise<string>;
+  bodyUsed: boolean;
+  headers: any;
+  ok: boolean;
+  resp: FetchBlobResponse;
+  rnfbResp: FetchBlobResponse;
+  rnfbRespInfo: RNFetchBlobResponseInfo;
+  status: number;
+  type: string;
 }
 
 /**
  * RNFetchBlob response object class.
  */
 export interface FetchBlobResponse {
-    taskId: string;
-    /**
-     * get path of response temp file
-     * @return File path of temp file.
-     */
-    path(): string;
-    type: "base64" | "path" | "utf8";
-    data: any;
-    /**
-     * Convert result to javascript RNFetchBlob object.
-     * @return Return a promise resolves Blob object.
-     */
-    blob(contentType: string, sliceSize: number): Promise<PolyfillBlob>;
-    /**
-     * Convert result to text.
-     * @return Decoded base64 string.
-     */
-    text(): string | Promise<any>;
-    /**
-     * Convert result to JSON object.
-     * @return Parsed javascript object.
-     */
-    json(): any;
-    /**
-     * Return BASE64 string directly.
-     * @return BASE64 string of response body.
-     */
-    base64(): any;
-    /**
-     * Remove cahced file
-     */
-    flush(): void;
-    respInfo: RNFetchBlobResponseInfo;
-    info(): RNFetchBlobResponseInfo;
-    session(name: string): RNFetchBlobSession | null;
-    /**
-     * Read file content with given encoding, if the response does not contains
-     * a file path, show warning message
-     * @param  encode Encode type, should be one of `base64`, `ascrii`, `utf8`.
-     */
-    readFile(encode: Encoding): Promise<any> | null;
-    /**
-     * Start read stream from cached file
-     * @param  encode Encode type, should be one of `base64`, `ascrii`, `utf8`.
-     */
-    readStream(encode: Encoding): RNFetchBlobStream | null;
+  taskId: string;
+  /**
+   * get path of response temp file
+   * @return File path of temp file.
+   */
+  path(): string;
+  type: "base64" | "path" | "utf8";
+  data: any;
+  /**
+   * Convert result to javascript RNFetchBlob object.
+   * @return Return a promise resolves Blob object.
+   */
+  blob(contentType: string, sliceSize: number): Promise<PolyfillBlob>;
+  /**
+   * Convert result to text.
+   * @return Decoded base64 string.
+   */
+  text(): string | Promise<any>;
+  /**
+   * Convert result to JSON object.
+   * @return Parsed javascript object.
+   */
+  json(): any;
+  /**
+   * Return BASE64 string directly.
+   * @return BASE64 string of response body.
+   */
+  base64(): any;
+  /**
+   * Remove cahced file
+   */
+  flush(): void;
+  respInfo: RNFetchBlobResponseInfo;
+  info(): RNFetchBlobResponseInfo;
+  session(name: string): RNFetchBlobSession | null;
+  /**
+   * Read file content with given encoding, if the response does not contains
+   * a file path, show warning message
+   * @param  encode Encode type, should be one of `base64`, `ascrii`, `utf8`.
+   */
+  readFile(encode: Encoding): Promise<any> | null;
+  /**
+   * Start read stream from cached file
+   * @param  encode Encode type, should be one of `base64`, `ascrii`, `utf8`.
+   */
+  readStream(encode: Encoding): RNFetchBlobStream | null;
 }
 
 export interface PolyfillFileReader extends EventTarget {
-    isRNFBPolyFill: boolean;
-    onloadstart(e: Event): void;
-    onprogress(e: Event): void;
-    onload(e: Event): void;
-    onabort(e: Event): void;
-    onerror(e: Event): void;
-    onloadend(e: Event): void;
-
-    abort(): void;
-    readAsArrayBuffer(b: PolyfillBlob): void;
-    readAsBinaryString(b: PolyfillBlob): void;
-    readAsText(b: PolyfillBlob, label?: string): void;
-    readAsDataURL(b: PolyfillBlob): void;
-
-    readyState: number;
-    result: number;
+  isRNFBPolyFill: boolean;
+  onloadstart(e: Event): void;
+  onprogress(e: Event): void;
+  onload(e: Event): void;
+  onabort(e: Event): void;
+  onerror(e: Event): void;
+  onloadend(e: Event): void;
+
+  abort(): void;
+  readAsArrayBuffer(b: PolyfillBlob): void;
+  readAsBinaryString(b: PolyfillBlob): void;
+  readAsText(b: PolyfillBlob, label?: string): void;
+  readAsDataURL(b: PolyfillBlob): void;
+
+  readyState: number;
+  result: number;
 }
 
 export declare namespace PolyfillFileReader {
-    const EMPTY: number;
-    const LOADING: number;
-    const DONE: number;
+  const EMPTY: number;
+  const LOADING: number;
+  const DONE: number;
 }
 
-export declare class PolyfillEvent {
-}
+export declare class PolyfillEvent {}
 
 export interface PolyfillProgressEvent extends EventTarget {
-    lengthComputable: boolean;
-    loaded: number;
-    total: number;
+  lengthComputable: boolean;
+  loaded: number;
+  total: number;
 }
 
 export declare class PolyfillBlob implements EventTarget {
-    /**
-     * RNFetchBlob Blob polyfill, create a Blob directly from file path, BASE64
-     * encoded data, and string. The conversion is done implicitly according to
-     * given `mime`. However, the blob creation is asynchronously, to register
-     * event `onCreated` is need to ensure the Blob is creadted.
-     *
-     * @param data Content of Blob object
-     * @param cType Content type settings of Blob object, `text/plain` by default
-     * @param defer When this argument set to `true`, blob constructor will not invoke blob created event automatically.
-     */
-    constructor(data: any, cType: any, defer: boolean);
-
-    /**
-     * Since Blob content will asynchronously write to a file during creation,
-     * use this method to register an event handler for Blob initialized event.
-     * @param  fn An event handler invoked when Blob created
-     * @return The Blob object instance itself
-     */
-    onCreated(fn: () => void): PolyfillBlob;
-
-    markAsDerived(): void;
-
-    /**
-     * Get file reference of the Blob object.
-     * @return Blob file reference which can be consumed by RNFetchBlob fs
-     */
-    getRNFetchBlobRef(): string;
-
-    /**
-     * Create a Blob object which is sliced from current object
-     * @param  start    Start byte number
-     * @param  end      End byte number
-     * @param  contentType Optional, content type of new Blob object
-     */
-    slice(start?: number, end?: number, contentType?: string): PolyfillBlob;
-
-    /**
-     * Read data of the Blob object, this is not standard method.
-     * @param  encoding Read data with encoding
-     */
-    readBlob(encoding: string): Promise<any>;
-
-    /**
-     * Release the resource of the Blob object.
-     * @nonstandard
-     */
-    close(): Promise<void>;
+  /**
+   * RNFetchBlob Blob polyfill, create a Blob directly from file path, BASE64
+   * encoded data, and string. The conversion is done implicitly according to
+   * given `mime`. However, the blob creation is asynchronously, to register
+   * event `onCreated` is need to ensure the Blob is creadted.
+   *
+   * @param data Content of Blob object
+   * @param cType Content type settings of Blob object, `text/plain` by default
+   * @param defer When this argument set to `true`, blob constructor will not invoke blob created event automatically.
+   */
+  constructor(data: any, cType: any, defer: boolean);
+
+  /**
+   * Since Blob content will asynchronously write to a file during creation,
+   * use this method to register an event handler for Blob initialized event.
+   * @param  fn An event handler invoked when Blob created
+   * @return The Blob object instance itself
+   */
+  onCreated(fn: () => void): PolyfillBlob;
+
+  markAsDerived(): void;
+
+  /**
+   * Get file reference of the Blob object.
+   * @return Blob file reference which can be consumed by RNFetchBlob fs
+   */
+  getRNFetchBlobRef(): string;
+
+  /**
+   * Create a Blob object which is sliced from current object
+   * @param  start    Start byte number
+   * @param  end      End byte number
+   * @param  contentType Optional, content type of new Blob object
+   */
+  slice(start?: number, end?: number, contentType?: string): PolyfillBlob;
+
+  /**
+   * Read data of the Blob object, this is not standard method.
+   * @param  encoding Read data with encoding
+   */
+  readBlob(encoding: string): Promise<any>;
+
+  /**
+   * Release the resource of the Blob object.
+   * @nonstandard
+   */
+  close(): Promise<void>;
 }
 
 export declare namespace PolyfillBlob {
-    function clearCache(): void;
+  function clearCache(): void;
 
-    function build(data: any, cType: any): Promise<PolyfillBlob>;
+  function build(data: any, cType: any): Promise<PolyfillBlob>;
 
-    function setLog(level: number): void;
+  function setLog(level: number): void;
 }
 
-export declare class PolyfillFile extends PolyfillBlob {
-}
+export declare class PolyfillFile extends PolyfillBlob {}
+
+export interface PolyfillXMLHttpRequest
+  extends PolyfillXMLHttpRequestEventTarget {
+  upload: PolyfillXMLHttpRequestEventTarget;
+  readonly UNSENT: number;
+  readonly OPENED: number;
+  readonly HEADERS_RECEIVED: number;
+  readonly LOADING: number;
+  readonly DONE: number;
+
+  /**
+   * XMLHttpRequest.open, always async, user and password not supported. When
+   * this method invoked, headers should becomes empty again.
+   * @param  method Request method
+   * @param  url Request URL
+   * @param  async Always async
+   * @param  user NOT SUPPORTED
+   * @param  password NOT SUPPORTED
+   */
+  open(
+    method: string,
+    url: string,
+    async: true,
+    user: any,
+    password: any
+  ): void;
+
+  /**
+   * Invoke this function to send HTTP request, and set body.
+   * @param body Body in RNfetchblob flavor
+   */
+  send(body: any): void;
+
+  overrideMimeType(mime: string): void;
+
+  setRequestHeader(name: string, value: string): void;
+
+  abort(): void;
+
+  getResponseHeader(field: string): string | null;
 
-export interface PolyfillXMLHttpRequest extends PolyfillXMLHttpRequestEventTarget {
-    upload: PolyfillXMLHttpRequestEventTarget;
-    readonly UNSENT: number;
-    readonly OPENED: number;
-    readonly HEADERS_RECEIVED: number;
-    readonly LOADING: number;
-    readonly DONE: number;
-
-    /**
-     * XMLHttpRequest.open, always async, user and password not supported. When
-     * this method invoked, headers should becomes empty again.
-     * @param  method Request method
-     * @param  url Request URL
-     * @param  async Always async
-     * @param  user NOT SUPPORTED
-     * @param  password NOT SUPPORTED
-     */
-    open(method: string, url: string, async: true, user: any, password: any): void;
-
-    /**
-     * Invoke this function to send HTTP request, and set body.
-     * @param body Body in RNfetchblob flavor
-     */
-    send(body: any): void;
-
-    overrideMimeType(mime: string): void;
-
-    setRequestHeader(name: string, value: string): void;
-
-    abort(): void;
-
-    getResponseHeader(field: string): string | null;
-
-    getAllResponseHeaders(): string | null;
-
-    onreadystatechange(e: Event): void;
-    readyState: number;
-    status: number;
-    statusText: string;
-    response: any;
-    responseText: any;
-    responseURL: string;
-    responseHeaders: any;
-    timeout: number;
-    responseType: string;
+  getAllResponseHeaders(): string | null;
+
+  onreadystatechange(e: Event): void;
+  readyState: number;
+  status: number;
+  statusText: string;
+  response: any;
+  responseText: any;
+  responseURL: string;
+  responseHeaders: any;
+  timeout: number;
+  responseType: string;
 }
 
 export declare namespace PolyfillXMLHttpRequest {
-    const binaryContentTypes: string[];
-    const UNSENT: number;
-    const OPENED: number;
-    const HEADERS_RECEIVED: number;
-    const LOADING: number;
-    const DONE: number;
+  const binaryContentTypes: string[];
+  const UNSENT: number;
+  const OPENED: number;
+  const HEADERS_RECEIVED: number;
+  const LOADING: number;
+  const DONE: number;
 
-    function setLog(level: number): void;
+  function setLog(level: number): void;
 
-    function addBinaryContentType(substr: string): void;
+  function addBinaryContentType(substr: string): void;
 
-    function removeBinaryContentType(): void;
+  function removeBinaryContentType(): void;
 }
 
 export interface PolyfillXMLHttpRequestEventTarget extends EventTarget {
-    onabort(e: Event): void;
-    onerror(e: Event): void;
-    onload(e: Event): void;
-    onloadstart(e: Event): void;
-    onprogress(e: Event): void;
-    ontimeout(e: Event): void;
-    onloadend(e: Event): void;
+  onabort(e: Event): void;
+  onerror(e: Event): void;
+  onload(e: Event): void;
+  onloadstart(e: Event): void;
+  onprogress(e: Event): void;
+  ontimeout(e: Event): void;
+  onloadend(e: Event): void;
 }
 
 export interface Net {
-    /**
-     * Get cookie according to the given url.
-     * @param  domain Domain of the cookies to be removed, remove all
-     * @return     Cookies of a specific domain.
-     */
-    getCookies(domain: string): Promise<string[]>;
-
-    /**
-     * Remove cookies for a specific domain
-     * @param  domain Domain of the cookies to be removed, remove all
-     * cookies when this is null.
-     */
-    removeCookies(domain?: string): Promise<null>;
+  /**
+   * Get cookie according to the given url.
+   * @param  domain Domain of the cookies to be removed, remove all
+   * @return     Cookies of a specific domain.
+   */
+  getCookies(domain: string): Promise<string[]>;
+
+  /**
+   * Remove cookies for a specific domain
+   * @param  domain Domain of the cookies to be removed, remove all
+   * cookies when this is null.
+   */
+  removeCookies(domain?: string): Promise<null>;
 }
 
 type HashAlgorithm = "md5" | "sha1" | "sha224" | "sha256" | "sha384" | "sha512";
 export interface FS {
-    RNFetchBlobSession: RNFetchBlobSession;
-
-    /**
-     * Remove file at path.
-     * @param    path:string Path of target file.
-     */
-    unlink(path: string): Promise<void>;
-
-    /**
-     * Create a directory.
-     * @param  path Path of directory to be created
-     */
-    mkdir(path: string): Promise<void>;
-
-    /**
-     * Get a file cache session
-     * @param  name Stream ID
-     */
-    session(name: string): RNFetchBlobSession;
-
-    ls(path: string): Promise<string[]>;
-
-    /**
-     * Read the file from the given path and calculate a cryptographic hash sum over its contents.
-     *
-     * @param path Path to the file
-     * @param algorithm The hash algorithm to use
-     */
-    hash(path: string, algorithm: HashAlgorithm): Promise<string>;
-
-    /**
-     * Create file stream from file at `path`.
-     * @param  path   The file path.
-     * @param  encoding Data encoding, should be one of `base64`, `utf8`, `ascii`
-     * @param  bufferSize Size of stream buffer.
-     * @return RNFetchBlobStream stream instance.
-     */
-    readStream(path: string, encoding: Encoding, bufferSize?: number, tick?: number): Promise<RNFetchBlobReadStream>;
-
-    mv(path: string, dest: string): Promise<boolean>;
-
-    cp(path: string, dest: string): Promise<boolean>;
-
-    /**
-     * Create write stream to a file.
-     * @param  path Target path of file stream.
-     * @param  encoding Encoding of input data.
-     * @param  append  A flag represent if data append to existing ones.
-     * @return A promise resolves a `WriteStream` object.
-     */
-    writeStream(path: string, encoding: Encoding, append?: boolean): Promise<RNFetchBlobWriteStream>;
-
-    /**
-     * Write data to file.
-     * @param  path  Path of the file.
-     * @param  data Data to write to the file.
-     * @param  encoding Encoding of data (Optional).
-     */
-    writeFile(path: string, data: string | number[], encoding?: Encoding): Promise<void>;
-
-    appendFile(path: string, data: string | number[], encoding?: Encoding | "uri"): Promise<number>;
-
-    /**
-     * Wrapper method of readStream.
-     * @param  path Path of the file.
-     * @param  encoding Encoding of read stream.
-     */
-    readFile(path: string, encoding: Encoding, bufferSize?: number): Promise<any>;
-    /**
-     * Check if file exists and if it is a folder.
-     * @param  path Path to check
-     */
-    exists(path: string): Promise<boolean>;
-
-    createFile(path: string, data: string, encoding: Encoding): Promise<void>;
-
-    isDir(path: string): Promise<boolean>;
-
-    /**
-     * Show statistic data of a path.
-     * @param  path Target path
-     */
-    stat(path: string): Promise<RNFetchBlobStat>;
-
-    lstat(path: string): Promise<RNFetchBlobStat[]>;
-
-    /**
-     * Android only method, request media scanner to scan the file.
-     * @param  pairs Array contains Key value pairs with key `path` and `mime`.
-     */
-    scanFile(pairs: Array<{ [key: string]: string }>): Promise<void>;
-
-    dirs: Dirs;
-
-    slice(src: string, dest: string, start: number, end: number): Promise<void>;
-    asset(path: string): string;
-    df(): Promise<{ free: number, total: number }>;
+  RNFetchBlobSession: RNFetchBlobSession;
+
+  /**
+   * Remove file at path.
+   * @param    path:string Path of target file.
+   */
+  unlink(path: string): Promise<void>;
+
+  /**
+   * Create a directory.
+   * @param  path Path of directory to be created
+   */
+  mkdir(path: string): Promise<void>;
+
+  /**
+   * Get a file cache session
+   * @param  name Stream ID
+   */
+  session(name: string): RNFetchBlobSession;
+
+  ls(path: string): Promise<string[]>;
+
+  /**
+   * Read the file from the given path and calculate a cryptographic hash sum over its contents.
+   *
+   * @param path Path to the file
+   * @param algorithm The hash algorithm to use
+   */
+  hash(path: string, algorithm: HashAlgorithm): Promise<string>;
+
+  /**
+   * Create file stream from file at `path`.
+   * @param  path   The file path.
+   * @param  encoding Data encoding, should be one of `base64`, `utf8`, `ascii`
+   * @param  bufferSize Size of stream buffer.
+   * @return RNFetchBlobStream stream instance.
+   */
+  readStream(
+    path: string,
+    encoding: Encoding,
+    bufferSize?: number,
+    tick?: number
+  ): Promise<RNFetchBlobReadStream>;
+
+  mv(path: string, dest: string): Promise<boolean>;
+
+  cp(path: string, dest: string): Promise<boolean>;
+
+  /**
+   * Create write stream to a file.
+   * @param  path Target path of file stream.
+   * @param  encoding Encoding of input data.
+   * @param  append  A flag represent if data append to existing ones.
+   * @return A promise resolves a `WriteStream` object.
+   */
+  writeStream(
+    path: string,
+    encoding: Encoding,
+    append?: boolean
+  ): Promise<RNFetchBlobWriteStream>;
+
+  /**
+   * Write data to file.
+   * @param  path  Path of the file.
+   * @param  data Data to write to the file.
+   * @param  encoding Encoding of data (Optional).
+   */
+  writeFile(
+    path: string,
+    data: string | number[],
+    encoding?: Encoding
+  ): Promise<void>;
+
+  appendFile(
+    path: string,
+    data: string | number[],
+    encoding?: Encoding | "uri"
+  ): Promise<number>;
+
+  /**
+   * Wrapper method of readStream.
+   * @param  path Path of the file.
+   * @param  encoding Encoding of read stream.
+   */
+  readFile(path: string, encoding: Encoding, bufferSize?: number): Promise<any>;
+  /**
+   * Check if file exists and if it is a folder.
+   * @param  path Path to check
+   */
+  exists(path: string): Promise<boolean>;
+
+  createFile(path: string, data: string, encoding: Encoding): Promise<void>;
+
+  isDir(path: string): Promise<boolean>;
+
+  /**
+   * Show statistic data of a path.
+   * @param  path Target path
+   */
+  stat(path: string): Promise<RNFetchBlobStat>;
+
+  lstat(path: string): Promise<RNFetchBlobStat[]>;
+
+  /**
+   * Android only method, request media scanner to scan the file.
+   * @param  pairs Array contains Key value pairs with key `path` and `mime`.
+   */
+  scanFile(pairs: Array<{ [key: string]: string }>): Promise<void>;
+
+  dirs: Dirs;
+
+  slice(src: string, dest: string, start: number, end: number): Promise<void>;
+  asset(path: string): string;
+  df(): Promise<{ free: number; total: number }>;
 }
 
 export interface Dirs {
-    DocumentDir: string;
-    CacheDir: string;
-    PictureDir: string;
-    LibraryDir: string;
-    MusicDir: string;
-    MovieDir: string;
-    DownloadDir: string;
-    DCIMDir: string;
-    SDCardDir: string;
-    MainBundleDir: string;
+  DocumentDir: string;
+  CacheDir: string;
+  PictureDir: string;
+  LibraryDir: string;
+  MusicDir: string;
+  MovieDir: string;
+  DownloadDir: string;
+  DCIMDir: string;
+  SDCardDir: string;
+  MainBundleDir: string;
 }
 
 export interface RNFetchBlobWriteStream {
-    id: string;
-    encoding: string;
-    append: boolean;
+  id: string;
+  encoding: string;
+  append: boolean;
 
-    write(data: string): Promise<void>;
-    close(): void;
+  write(data: string): Promise<void>;
+  close(): void;
 }
 
 export interface RNFetchBlobReadStream {
-    path: string;
-    encoding: Encoding;
-    bufferSize?: number;
-    closed: boolean;
-    tick: number;
+  path: string;
+  encoding: Encoding;
+  bufferSize?: number;
+  closed: boolean;
+  tick: number;
 
-    open(): void;
+  open(): void;
 
-    onData(fn: (chunk: string | number[]) => void): void;
+  onData(fn: (chunk: string | number[]) => void): void;
 
-    onError(fn: (err: any) => void): void;
+  onError(fn: (err: any) => void): void;
 
-    onEnd(fn: () => void): void;
+  onEnd(fn: () => void): void;
 }
 
 export type Encoding = "utf8" | "ascii" | "base64";
 
 /* tslint:disable-next-line interface-name*/
 export interface IOSApi {
-    /**
-     * Open a file in {@link https://developer.apple.com/reference/uikit/uidocumentinteractioncontroller UIDocumentInteractionController},
-     * this is the default document viewer of iOS, supports several kinds of files. On Android, there's an similar method {@link android.actionViewIntent}.
-     * @param path This is a required field, the path to the document. The path should NOT contains any scheme prefix.
-     */
-    previewDocument(path: string): void;
-
-    /**
-     * Show options menu for interact with the file.
-     * @param path This is a required field, the path to the document. The path should NOT contains any scheme prefix.
-     */
-    openDocument(path: string): void;
+  /**
+   * Open a file in {@link https://developer.apple.com/reference/uikit/uidocumentinteractioncontroller UIDocumentInteractionController},
+   * this is the default document viewer of iOS, supports several kinds of files. On Android, there's an similar method {@link android.actionViewIntent}.
+   * @param path This is a required field, the path to the document. The path should NOT contains any scheme prefix.
+   */
+  openDocument(path: string): void;
+
+  /**
+   * Show options menu for interact with the file.
+   * @param path This is a required field, the path to the document. The path should NOT contains any scheme prefix.
+   */
+  previewDocument(path: string): void;
 }
 
 export interface AndroidDownloadOption {
-    /**
-     * Title string to be displayed when the file added to Downloads app.
-     */
-    title: string
-
-    /**
-     * File description to be displayed when the file added to Downloads app.
-     */
-    description: string
-
-    /**
-     * MIME string of the file.
-     */
-    mime: string
-
-    /**
-     * URI string of the file.
-     */
-    path: string
-
-    /**
-     * Boolean value that determines if notification will be displayed.
-     */
-    showNotification: boolean 
-}
+  /**
+   * Title string to be displayed when the file added to Downloads app.
+   */
+  title: string;
 
-export interface AndroidApi {
-    /**
-     * When sending an ACTION_VIEW intent with given file path and MIME type, system will try to open an
-     * App to handle the file. For example, open Gallery app to view an image, or install APK.
-     * @param path Path of the file to be opened.
-     * @param mime Basically system will open an app according to this MIME type.
-     */
-    actionViewIntent(path: string, mime: string): Promise<any>;
-
-    /**
-     * 
-     * This method brings up OS default file picker and resolves a file URI when the user selected a file.
-     * However, it does not resolve or reject when user dismiss the file picker via pressing hardware back button,
-     * but you can still handle this behavior via AppState.
-     * @param mime MIME type filter, only the files matches the MIME will be shown.
-     */
-    getContentIntent(mime: string): Promise<any>;
-
-    /**
-     * Using this function to add an existing file to Downloads app.
-     * @param options An object that for setting the title, description, mime, and notification of the item.
-     */
-    addCompleteDownload(options: AndroidDownloadOption): Promise<void>;
-
-    getSDCardDir(): Promise<string>;
-
-    getSDCardApplicationDir(): Promise<string>;
+  /**
+   * File description to be displayed when the file added to Downloads app.
+   */
+  description: string;
+
+  /**
+   * MIME string of the file.
+   */
+  mime: string;
+
+  /**
+   * URI string of the file.
+   */
+  path: string;
+
+  /**
+   * Boolean value that determines if notification will be displayed.
+   */
+  showNotification: boolean;
 }
 
-type Methods = "POST" | "GET" | "DELETE" | "PUT" | "post" | "get" | "delete" | "put";
+export interface AndroidApi {
+  /**
+   * When sending an ACTION_VIEW intent with given file path and MIME type, system will try to open an
+   * App to handle the file. For example, open Gallery app to view an image, or install APK.
+   * @param path Path of the file to be opened.
+   * @param mime Basically system will open an app according to this MIME type.
+   */
+  actionViewIntent(path: string, mime: string): Promise<any>;
+
+  /**
+   *
+   * This method brings up OS default file picker and resolves a file URI when the user selected a file.
+   * However, it does not resolve or reject when user dismiss the file picker via pressing hardware back button,
+   * but you can still handle this behavior via AppState.
+   * @param mime MIME type filter, only the files matches the MIME will be shown.
+   */
+  getContentIntent(mime: string): Promise<any>;
+
+  /**
+   * Using this function to add an existing file to Downloads app.
+   * @param options An object that for setting the title, description, mime, and notification of the item.
+   */
+  addCompleteDownload(options: AndroidDownloadOption): Promise<void>;
+
+  getSDCardDir(): Promise<string>;
+
+  getSDCardApplicationDir(): Promise<string>;
+}
+
+type Methods =
+  | "POST"
+  | "GET"
+  | "DELETE"
+  | "PUT"
+  | "post"
+  | "get"
+  | "delete"
+  | "put";
 
 /**
  * A declare class inherits Promise, it has extra method like progress, uploadProgress,
  * and cancel which can help managing an asynchronous task's state.
  */
 export interface StatefulPromise<T> extends Promise<T> {
-    /**
-     * Cancel the request when invoke this method.
-     */
-    cancel(cb?: (reason: any) => void): StatefulPromise<FetchBlobResponse>;
-
-    /**
-     * Add an event listener which triggers when data receiving from server.
-     */
-    progress(callback: (received: number, total: number) => void): StatefulPromise<FetchBlobResponse>;
-
-    /**
-     * Add an event listener with custom configuration
-     */
-    progress(config: { count?: number, interval?: number }, callback: (received: number, total: number) => void): StatefulPromise<FetchBlobResponse>;
-
-    /**
-     * Add an event listener with custom configuration.
-     */
-    uploadProgress(callback: (sent: number, total: number) => void): StatefulPromise<FetchBlobResponse>;
-
-    /**
-     * Add an event listener with custom configuration
-     */
-    uploadProgress(config: { count?: number, interval?: number }, callback: (sent: number, total: number) => void): StatefulPromise<FetchBlobResponse>;
-
-    /**
-     * An IOS only API, when IOS app turns into background network tasks will be terminated after ~180 seconds,
-     * in order to handle these expired tasks, you can register an event handler, which will be called after the
-     * app become active.
-     */
-    expire(callback: () => void): StatefulPromise<void>;
+  /**
+   * Cancel the request when invoke this method.
+   */
+  cancel(cb?: (reason: any) => void): StatefulPromise<FetchBlobResponse>;
+
+  /**
+   * Add an event listener which triggers when data receiving from server.
+   */
+  progress(
+    callback: (received: number, total: number) => void
+  ): StatefulPromise<FetchBlobResponse>;
+
+  /**
+   * Add an event listener with custom configuration
+   */
+  progress(
+    config: { count?: number; interval?: number },
+    callback: (received: number, total: number) => void
+  ): StatefulPromise<FetchBlobResponse>;
+
+  /**
+   * Add an event listener with custom configuration.
+   */
+  uploadProgress(
+    callback: (sent: number, total: number) => void
+  ): StatefulPromise<FetchBlobResponse>;
+
+  /**
+   * Add an event listener with custom configuration
+   */
+  uploadProgress(
+    config: { count?: number; interval?: number },
+    callback: (sent: number, total: number) => void
+  ): StatefulPromise<FetchBlobResponse>;
+
+  /**
+   * An IOS only API, when IOS app turns into background network tasks will be terminated after ~180 seconds,
+   * in order to handle these expired tasks, you can register an event handler, which will be called after the
+   * app become active.
+   */
+  expire(callback: () => void): StatefulPromise<void>;
 }
 
 export declare class RNFetchBlobSession {
-    constructor(name: string, list: string[]);
+  constructor(name: string, list: string[]);
 
-    add(path: string): RNFetchBlobSession;
+  add(path: string): RNFetchBlobSession;
 
-    remove(path: string): RNFetchBlobSession;
+  remove(path: string): RNFetchBlobSession;
 
-    dispose(): Promise<void>;
+  dispose(): Promise<void>;
 
-    list(): string[];
+  list(): string[];
 
-    name: string;
+  name: string;
 
-    static getSession(name: string): any;
+  static getSession(name: string): any;
 
-    static setSession(name: string): void;
+  static setSession(name: string): void;
 
-    static removeSession(name: string): void;
+  static removeSession(name: string): void;
 }
 
 /**
  * A set of configurations that will be injected into a fetch method, with the following properties.
  */
 export interface RNFetchBlobConfig {
-    /**
-     * When this property is true, the downloaded data will overwrite the existing file. (true by default)
-     */
-    overwrite?: boolean;
-
-    /**
-     * Set timeout of the request (in milliseconds).
-     */
-    timeout?: number;
-
-    /**
-     * Set this property to true to display a network indicator on status bar, this feature is only supported on IOS.
-     */
-    indicator?: boolean;
-
-    /**
-     * Set this property to true will allow the request create connection with server have self-signed SSL
-     * certification. This is not recommended to use in production.
-     */
-    trusty?: boolean;
-
-    /**
-     * Set this property to true will only do requests through the WiFi interface, and fail otherwise.
-     */
-    wifiOnly?: boolean;
-
-    /**
-     * Set this property so redirects are not automatically followed.
-     */
-    followRedirect?: boolean;
-
-    /**
-     * Set this property to true will makes response data of the fetch stored in a temp file, by default the temp
-     * file will stored in App's own root folder with file name template RNFetchBlob_tmp${timestamp}.
-     */
-    fileCache?: boolean;
-
-    /**
-     * Set this property to change temp file extension that created by fetch response data.
-     */
-    appendExt?: string;
-
-    /**
-     * When this property has value, fetch API will try to store response data in the path ignoring fileCache and
-     * appendExt property.
-     */
-    path?: string;
-
-    session?: string;
-
-    addAndroidDownloads?: AddAndroidDownloads;
-
-    /**
-     * Fix IOS request timeout issue #368 by change default request setting to defaultSessionConfiguration, and make backgroundSessionConfigurationWithIdentifier optional
-     */
-    IOSBackgroundTask?: boolean;
+  /**
+   * When this property is true, the downloaded data will overwrite the existing file. (true by default)
+   */
+  overwrite?: boolean;
+
+  /**
+   * Set timeout of the request (in milliseconds).
+   */
+  timeout?: number;
+
+  /**
+   * Set this property to true to display a network indicator on status bar, this feature is only supported on IOS.
+   */
+  indicator?: boolean;
+
+  /**
+   * Set this property to true will allow the request create connection with server have self-signed SSL
+   * certification. This is not recommended to use in production.
+   */
+  trusty?: boolean;
+
+  /**
+   * Set this property to true will only do requests through the WiFi interface, and fail otherwise.
+   */
+  wifiOnly?: boolean;
+
+  /**
+   * Set this property so redirects are not automatically followed.
+   */
+  followRedirect?: boolean;
+
+  /**
+   * Set this property to true will makes response data of the fetch stored in a temp file, by default the temp
+   * file will stored in App's own root folder with file name template RNFetchBlob_tmp${timestamp}.
+   */
+  fileCache?: boolean;
+
+  /**
+   * Set this property to change temp file extension that created by fetch response data.
+   */
+  appendExt?: string;
+
+  /**
+   * When this property has value, fetch API will try to store response data in the path ignoring fileCache and
+   * appendExt property.
+   */
+  path?: string;
+
+  session?: string;
+
+  addAndroidDownloads?: AddAndroidDownloads;
+
+  /**
+   * Fix IOS request timeout issue #368 by change default request setting to defaultSessionConfiguration, and make backgroundSessionConfigurationWithIdentifier optional
+   */
+  IOSBackgroundTask?: boolean;
 }
 
 export interface AddAndroidDownloads {
-    /**
-     * download file using Android download manager or not.
-     */
-    useDownloadManager?: boolean;
-    /**
-     * title of the file
-     */
-    title?: string;
-    /**
-     * File description of the file.
-     */
-    description?: string;
-    /**
-     * The destination which the file will be downloaded, it SHOULD be a location on external storage (DCIMDir).
-     */
-    path?: string;
-    /**
-     * MIME type of the file. By default is text/plain
-     */
-    mime?: string;
-    /**
-     * A boolean value, see Officail Document
-     * (https://developer.android.com/reference/android/app/DownloadManager.html#addCompletedDownload(java.lang.String, java.lang.String, boolean, java.lang.String, java.lang.String, long, boolean))
-     */
-    mediaScannable?: boolean;
-    /**
-     * A boolean value decide whether show a notification when download complete.
-     */
-    notification?: boolean;
+  /**
+   * download file using Android download manager or not.
+   */
+  useDownloadManager?: boolean;
+  /**
+   * title of the file
+   */
+  title?: string;
+  /**
+   * File description of the file.
+   */
+  description?: string;
+  /**
+   * The destination which the file will be downloaded, it SHOULD be a location on external storage (DCIMDir).
+   */
+  path?: string;
+  /**
+   * MIME type of the file. By default is text/plain
+   */
+  mime?: string;
+  /**
+   * A boolean value, see Officail Document
+   * (https://developer.android.com/reference/android/app/DownloadManager.html#addCompletedDownload(java.lang.String, java.lang.String, boolean, java.lang.String, java.lang.String, long, boolean))
+   */
+  mediaScannable?: boolean;
+  /**
+   * A boolean value decide whether show a notification when download complete.
+   */
+  notification?: boolean;
 }
 
 export interface RNFetchBlobResponseInfo {
-    taskId: string;
-    state: string;
-    headers: any;
-    redirects: string[];
-    status: number;
-    respType: "text" | "blob" | "" | "json";
-    rnfbEncode: "path" | "base64" | "ascii" | "utf8";
-    timeout: boolean;
+  taskId: string;
+  state: string;
+  headers: any;
+  redirects: string[];
+  status: number;
+  respType: "text" | "blob" | "" | "json";
+  rnfbEncode: "path" | "base64" | "ascii" | "utf8";
+  timeout: boolean;
 }
 
 export interface RNFetchBlobStream {
-    onData(): void;
-    onError(): void;
-    onEnd(): void;
+  onData(): void;
+  onError(): void;
+  onEnd(): void;
 }
 
-export declare class RNFetchBlobFile {
-}
+export declare class RNFetchBlobFile {}
 
 export declare class RNFetchBlobStat {
-    lastModified: number;
-    size: number;
-    type: "directory" | "file";
-    path: string;
-    filename: string;
+  lastModified: number;
+  size: number;
+  type: "directory" | "file";
+  path: string;
+  filename: string;
 }
diff --git a/ios.js b/ios.js
index 8e4cf140a..fdc88ab49 100644
--- a/ios.js
+++ b/ios.js
@@ -7,34 +7,32 @@ import {
   DeviceEventEmitter,
   Platform,
   NativeAppEventEmitter,
-} from 'react-native'
+} from "react-native";
 
-const RNFetchBlob:RNFetchBlobNative = NativeModules.RNFetchBlob
+const RNFetchBlob: RNFetchBlobNative = NativeModules.RNFetchBlob;
 
 /**
- * Open a file using UIDocumentInteractionController
+ * Preview a file using UIDocumentInteractionController
  * @param  {string} path Path of the file to be open.
  * @param  {string} scheme URI scheme that needs to support, optional
  * @return {Promise}
  */
-function previewDocument(path:string, scheme:string) {
-  if(Platform.OS === 'ios')
-    return RNFetchBlob.previewDocument('file://' + path, scheme)
-  else
-    return Promise.reject('RNFetchBlob.openDocument only supports IOS.')
+function previewDocument(path: string, scheme: string) {
+  if (Platform.OS === "ios")
+    return RNFetchBlob.previewDocument("file://" + path, scheme);
+  else return Promise.reject("RNFetchBlob.previewDocument only supports IOS.");
 }
 
 /**
- * Preview a file using UIDocumentInteractionController
+ * Open a file using UIDocumentInteractionController
  * @param  {string} path Path of the file to be open.
  * @param  {string} scheme URI scheme that needs to support, optional
  * @return {Promise}
  */
-function openDocument(path:string, scheme:string) {
-  if(Platform.OS === 'ios')
-    return RNFetchBlob.openDocument('file://' + path, scheme)
-  else
-    return Promise.reject('RNFetchBlob.previewDocument only supports IOS.')
+function openDocument(path: string, scheme: string) {
+  if (Platform.OS === "ios")
+    return RNFetchBlob.openDocument("file://" + path, scheme);
+  else return Promise.reject("RNFetchBlob.openDocument only supports IOS.");
 }
 
 /**
@@ -43,12 +41,12 @@ function openDocument(path:string, scheme:string) {
  * @param  {string} url URL of the resource, only file URL is supported
  * @return {Promise}
  */
-function excludeFromBackupKey(path:string) {
-  return RNFetchBlob.excludeFromBackupKey('file://' + path);
+function excludeFromBackupKey(path: string) {
+  return RNFetchBlob.excludeFromBackupKey("file://" + path);
 }
 
 export default {
   openDocument,
   previewDocument,
-  excludeFromBackupKey
-}
+  excludeFromBackupKey,
+};