react-relay-network-layer/es/relayMutation.js

Network Layer for React Relay and Express (Batch Queries, AuthToken, Logging, Retry)

/* eslint-disable no-param-reassign, no-use-before-define, prefer-template */
export default function mutation(relayRequest, fetchWithMiddleware) {
  const commonReq = {
    method: 'POST',
    relayReqId: relayRequest.getID ? relayRequest.getID() : `mutation${Math.random()}`,
    relayReqObj: relayRequest,
    relayReqType: 'mutation'
  };
  let req;

  if (hasFiles(relayRequest)) {
    req = mutationWithFiles(commonReq, relayRequest);
  } else {
    req = mutationWithoutFiles(commonReq, relayRequest);
  }

  return fetchWithMiddleware(req).then(({
    data
  }) => relayRequest.resolve({
    response: data
  })).catch(err => relayRequest.reject(err));
}

function hasFiles(relayRequest) {
  return !!(relayRequest.getFiles && relayRequest.getFiles());
}

function mutationWithFiles(req, relayRequest) {
  req.headers = {};

  if (hasFiles(relayRequest)) {
    const files = relayRequest.getFiles();

    if (!global.FormData) {
      throw new Error('Uploading files without `FormData` not supported.');
    }

    const formData = new FormData();
    formData.append('id', req.relayReqId);
    formData.append('query', relayRequest.getQueryString());
    formData.append('variables', JSON.stringify(relayRequest.getVariables()));

    if (files) {
      Object.keys(files).forEach(filename => {
        if (Array.isArray(files[filename])) {
          files[filename].forEach(file => {
            formData.append(filename, file);
          });
        } else {
          formData.append(filename, files[filename]);
        }
      });
    }

    req.body = formData;
  }

  return req;
}

function mutationWithoutFiles(req, relayRequest) {
  req.headers = {
    Accept: '*/*',
    'Content-Type': 'application/json'
  };
  req.body = JSON.stringify({
    id: req.relayReqId,
    query: relayRequest.getQueryString(),
    variables: relayRequest.getVariables()
  });
  return req;
}