I am using React native fetch blob store the image but when i use rnfetchblob i am getting error polyfill is undefined

  ChangePicture=()=>{
    const Blob=RNFetchBlob.polyfill.Blob
    const fs = RNFetchBlob.fs
    window.XMLHttpRequest = RNFetchBlob.polyfill.XMLHttpRequest
    window.Blob = Blob 
}

And my used liked this but i am getting as polyfill is undefined
