constructor(props) {

    super(props)

    this.state = {

      Nik: '',
      UserPassword: ''

    }

  }
  UserLoginFunction = () =>{
    const { Nik }  = this.state ;
    const { UserPassword }  = this.state ;


  fetch('url', {
    method: 'POST',
    headers: {
      'Accept': 'application/json',
      'Content-Type': 'application/json',
    },
    body: JSON.stringify({

      user: Nik,

      pass: UserPassword

    })

  }).then((response) => response.json())
      .then((responseJson) => {
          console.log(responseJson)
        })
      .catch((error) => {
          console.log(error)
      });