Add a custom context

[alberthuang24]

For the front-end, the access token may be stored anywhere. Maybe localStorage, cookies, indexedDB.

So we might be able to provide a similar API

mesh.addCustomContextBuilder(() => {
  const accessToken = localStorage.get(‘accessToken');
  return {
    accessToken
  }
});

sources:
  - name: MyGraphQLApi
    handler:
      graphql:
        endpoint: http://my-service-url:3000/graphql
        operationHeaders:
          # Please do not use capital letters while getting the headers
          Authorization: Bearer {context.accessToken}
          # You can also access to the cookies like below;
          # Authorization: Bearer {context.cookies.myApiToken}