iOS await + yield giving syntax error

This as a cell fails on iOS:
await new Promise(resolve => setTimeout(resolve, 100));
yield ‘done’;

I made a simple notebook to repro:

On iOS I see “Syntax Error: Unexpected token ‘*’. Expected an opening ‘(’ before a async function’s parameter list”. Note that if I remove the await line or the yield line, the error goes away.

On desktop chrome, it works fine and yields ‘done’ after 100ms.

Have you seen this before?

Sadly, async generators are not yet supported in Safari. However, you can often achieve the same effect in a (non-async) generator by yielding a promise, since Observable automatically waits for the promise to resolve before pulling the next value from the generator.