Sending YAML document from JavaScript (React)

SendYamlFromJavascript.js

import * as React from 'react'

function PickYamlFile() {

  onInputChange = async (evt) => {
    const file = evt.currentTarget.files[0]
    const url = myHost() + '/import'

    // Important to wrap the YAML with FormData encoding as YAML may contain % or other difficult characters.
    const data = new FormData()
    data.append('file', file)

    // TODO: P2 - The error handling around this is weak
      
    await fetch(url , {
      method: 'POST',
        // Note:  Don't add any additional Content-Type or enctype header.
        headers: {
        'Access-Control-Allow-Origin': '*',
      },
      body: data})
  }

  return {
      <input type="file" id="fileElem" accept=".yaml, .yml" style={{display: 'none'}} onChange={onInputChange} />
  }
}

//  See also: https://gist.github.com/rjattrill/7415a9af49aeb7fa63c63c1caec8421c for a Sinatra receiver