Instead of prohibiting ‘return undefined’ (#8669), we require that a
function must return an explicit value always or never. This prevents
you from forgetting to return a value in some cases. It will also be
important for TypeScript, which distinguishes between undefined and
void.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
This is a pretty straightforward conversion.
The bulk of the diff is just changing emoji.js
to ES6 syntax.
There is one little todo that can be deferred
to the next commit--we are now set up to have
markdown.js require emoji.js directly, since
it is no longer on `window`.