graphQLFetch.js

export default async function graphQLFetch(query, variables = {}, multipart = false){
  let request;
  if(multipart){
    const data = {
      operations: JSON.stringify({
        query,
        variables: {
          ...variables,
          file: null
        }
      }),
      map: JSON.stringify({
        '0': [
          'variables.file'
        ]
      })
    };
    const requestBody = new FormData();
    for(const name in data) {
      requestBody.append(name, data[name]);
    }
    requestBody.append('0', variables.file);
    request = {
      method: 'POST',
      body: requestBody
    }
  } else {
    request = {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ query, variables })
    }
  }
  const response = await fetch('/graphql', request);
  const responseBody = await response.text();
  const result = JSON.parse(responseBody);
  return result.data;
}