A handler may return a boolean (legacy interface), a Promise, or a generator that yields to await async values. The render driver resolves all three, so operators written against the legacy => boolean signature keep working.
boolean
Promise
yield
=> boolean
A handler may return a
boolean(legacy interface), aPromise, or a generator thatyields to await async values. The render driver resolves all three, so operators written against the legacy=> booleansignature keep working.