functions.js

  handleFileUpload = (event) => {
    this.setState({ file: event.target.files });
  };

  submitFile = (event) => {
    event.preventDefault();
    const formData = new FormData();
    formData.append('file', this.state.file[0]);
    axios
      .post(
        'https://your-api-endpoint.com/upload',
        formData,
        {
          headers: {
            'Content-Type': 'multipart/form-data',
          }
        }
      )
      .then((response) => {
        // handle your response
      })
      .catch(() => {
        // handle your error
      });
  };