devour-jsonapi-client/middleware/json-api/req-headers.js

Don't just consume your JSON API, Devour it...

const isEmpty = require('lodash').isEmpty

module.exports = {
  name: 'HEADER',
  req: (payload)=> {
    if (!isEmpty(payload.jsonApi.headers)) {
      payload.req.headers = Object.assign({}, payload.req.headers, payload.jsonApi.headers)
    }
    return payload
  }
}