Using Vision’s global contexts for auth data

I seem to be on a hapi theme right now. It’s new to me and seems a bit less well covered than Express in Google results, so I figure I might as well write stuff down and hope it helps someone else.

The problem

I was trying to do the usual thing for the navbar, only showing the register/login/register buttons when it makes sense. But how to know which to display? I don’t want to add loggedIn to the context for every h.view() call, that’s just ugly.

The solution I found

When setting up the server views, you can supply a context to Vision:

The global context option can be either an object or a function that takes the request … The contents of the context will be merged with anything else you supply to a page being rendered.

So - building on that:

function buildVisionContext(request) {
  return {
    loggedIn: request.auth.isAuthenticated
  };
}

async function registerVision(server) {
  let cached;

  if (!process.env.NODE_ENV || process.env.NODE_ENV === "development") {
    cached = false;
  } else {
    cached = true;
  }
  server.log(["debug"], `Caching templates: ${cached}`);
  server.views({
    engines: { ejs: require("ejs")},
    relativeTo: __dirname + "/../",
    path: 'templates',
    isCached: cached,
    context: buildVisionContext
  });
}

And now, every page rendered with h.view() will automatically have that variable available to it.

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