Added [app.serveOrigin] UnhandledPromiseRejectionWarning

_Originally posted by @pavelfeldman in https://github.com/GoogleChromeLabs/carlo/issues/45#issuecomment-436094420_ _Commit: https://github.com/GoogleChromeLabs/carlo/commit/e384301633c59061bac6aa6959e4566b4e45c598_

App.serveOrigin(origin) doesn’t seem to work properly.

(node:2452) UnhandledPromiseRejectionWarning: TypeError: app.serveOrigin is not a function
    at carlo.launch.then (D:\Dokumenty\carlo-serve-origin-test\index.js:5:7)
    at process.internalTickCallback (internal/process/next_tick.js:77:7)
(node:2452) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:2452) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

[pavelfeldman]

The idea behind serveOrigin is that it is used for dev mode and overrides serveFolder. Carlo should not be used without serveFolder, because it defeats Carlo’s purpose. You can run express and point your browser to the port if all you want is serve.

[dacturne]

Perhaps it could be changed in load() ?

load(uri = '') {
  if (!this.www_.size) {
    if (this.wwwOrigin_) {
      this.www_.set('/');
    } else {
      this.page_.close();
      throw new Error('Please call app.serveFolder(__dirname) or point to ' +
                      'other folder(s) with your web files');
    }
  }
  return this.page_.goto(`https://domain/${uri}`, {timeout: 0});
}

And it’d be implicitly set, saving from confusion as mentioned above

app.serveOrigin('https://example.org');
// app.serveFolder('/');
await app.load(); // no URI passed