Ionic + Uploadcare error - Property 'json' does not exist on type 'Object'

Hi, so I’m trying to upload an image to UploadCare, but the event.json() comes with an error saying

Property ‘json’ does not exist on type ‘Object’

here’s my code:

uploadPic(event){
    const files = event.target.files

    const data =  new FormData()
    data.append('file', files[0])
    data.append('UPLOADCARE_STORE', '1')
    data.append('UPLOADCARE_PUB_KEY', 'myapikey')
    this.http.post('https://upload.uploadcare.com/base/', data).subscribe(event=>{
    console.log(event)
    const uuid = event.json().File
    this.mainuser.update({
      profilePic: uuid
    })
    })
  }