PDE-2564: core(feat): allow using await in inline function source (9.x backport)

[eliangcs]

This is a 9.x backport merging into the release-9.x branch. I created this new branch release-9.x from tag zapier-platform-cli@9.4.2 so we can release more 9.x versions from that branch. Once this PR is approved, I'll merge and cut a release 9.5.0.

This PR addresses two Jira tickets:

• PDE-2564: Add async/await support for Visual Builder (hackathon project)
• PDE-2465: Backport fix(core): make sure requests made outside z.request are logged #387 to 9.x to make sure calling z.request() in the legacy script is logged

For PDE-2564, this patch allows developers to use the await operator in Visual Builder's Code Mode. For example, Visual Builder may generate this code for auth testing:

const options = {
  url: 'https://auth-json-server.zapier-staging.com/me',
  method: 'GET',
  headers: {
    'X-Api-Key': bundle.authData.api_key
  }
};
return z.request(options)
  .then((response) => {
    response.throwForStatus();
    return response.json;
  });

Now with the support for the await operator, developers can write this:

const options = {
  url: 'https://auth-json-server.zapier-staging.com/me',
  method: 'GET',
  headers: {
    'X-Api-Key': bundle.authData.api_key
  }
};
const response = await z.request(options);
response.throwForStatus();
return response.json;

[xavdid]

Nice! My only thought here is if it being async changes our error-handling story at all. I don't think it does (and I see you've got a test), but I could see a situation where wherever this created function is called (the execute command handler, I think?) we do a catch but don't expect a rejected promise. So, if you haven't, that bears looking into.

The only other consideration isn't related to the content of this PR exactly, but about the backporting. Apps that have been running continuously (most public apps, which probably don't have their lambda functions pruned) could still be running on Node 8. It's possible that they don't work on later node versions, but we don't know it yet. We could be poking the bear by refreshing apps that have been humming along nicely. It's probably fine, but that was an area of concern that popped up as I was thinking through this.

Also, my guess is that we'll take godzilla apps from 9.x right to 11.x, so we probably don't need a 10.x release, FWIW.

Great job!

[eliangcs]

@xavdid thanks for the great feedback! I didn't think that much so I took a second look.

I think we can safely assume the core always calls the created function asynchronously. The command handler named app is created here:

zapier-platform/packages/core/src/create-app.js

Lines 43 to 45 in 717bbed

	const app = createCommandHandler(frozenCompiledApp);
	return applyMiddleware(befores, afters, app);

In applyMiddleware, there's a resolve wrapping around the app() call:

zapier-platform/packages/core/src/middleware.js

Lines 88 to 92 in 717bbed

	const promise = beforeMiddleware(input).then((newInput) => {
	return resolve(app(newInput))
	.then(ensureEnvelope)
	.then((output) => {

This means even if app doesn't return a Promise, that resolve will make it a Promise. So I think we're safe replacing new Fucntion() with new AsyncFunction().

Good call on the Node 8 concern! I looked into the database. No Visual Builder apps are running on Node.js 8. I think they all got upgraded in the previously 9.x releases.

[xavdid]

Sweet! Carry on 🚢