react-form.js

handleSubmit(e) {
    e.preventDefault();
    const token = localStorage.getItem(Constants.key_api_auth_token);
    if(this.state.name && this.state.cost) {
        const formData = new FormData();
        if(this.state.file) {
          formData.append('file',this.state.file);
        }
        formData.append('name', this.state.name);
        formData.append('cost', this.state.cost);
        axios.post(Constants.api_url + '/api/rewardItems?token='+token,
        formData).then((response) => {
          this.setState({
            name: "",
            cost: "",
            file: null
          })
          this.getRewardItems();
        }).catch(function (error) {
          this.setState({error: true});
        });
    } else {
      this.setState({
        error: true
      })
    }
  }