Code cleanup

const Api = {

  signUp(user) {
    console.log(Constant.default.apiUrl);
    return fetch(Constant.default.apiUrl + '/signup', {
      method: 'POST',
      headers: {
        'Accept': 'application/json',
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(user)
    })
    .then(response => response.json())
    .then(responseJson => {
      if (responseJson.success) {
        console.log(responseJson.userData);
        return responseJson.userData;
      } else {
        throw responseJson;
      }
    })
    .catch(err => {
        throw {
            // this just makes the error source obvious
            message: 'Error in sign up',
            error: err
        };
    });
  },

  login(user) {
    return fetch(Constant.default.apiUrl + '/login', {
      method: 'POST',
      headers: {
        'Accept': 'application/json',
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(user)
    })
    .then(response => response.json())
    .then(responseJson => {
      console.log("responsejson " + responseJson);
      console.log("laaaa");
      if (responseJson.success) {
        return responseJson.userData;
      } else {
        throw responseJson;
      }
    })
    .catch(err => {
        throw {
            // this just makes the error source obvious
            message: 'Error in login',
            error: err
        };
    });
  }
};

export default Api;

function register() {

  if (this.state.password.length > 3 && this.state.password === this.state.confirmPassword) {
    var user = {
      firstName: this.props.firstName,
      lastName: this.props.lastName,
      emailAddress: this.state.emailAddress,
      password: this.state.password,
    };

    Api.signUp(user)
    .then((result) => {
        console.log("sign up result: " + JSON.stringify(result));
        return Api.login(user);
    })
    .then(result => {
      console.log("login result: " + JSON.stringify(result));
    })
    .catch(resultErr => console.log(resultErr));
  } else {
    this.setState({
      error: true,
      errorMessage: 'Veuillez remplir les champs correctement'
    });
  }
};