Support set/clearTimeout

[p-bakker]

The settimeout & clearTimeout API's are widely available in JavaScript runtimes, but not part of the EcmaScript specification. They are defined by https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#dom-settimeout-dev

It makes sense to support these API's in Rhino, but only as an opt-in feature, similar to #1012

Some support for these API's got added in v1.7.14 (see #1003), but only to aid in a more correct 'score'on the Kangax Compat table for the Promises support that landed in v1.7.14.

This case is to:

• make the impl. spec compliant
• make the impl. work correctly in the shell
• make the implementation available behind a feature flag, also outside of the shell

[MaxisTekfield]

Is rhino going to support async programming? Such as Promise APIs.

[p-bakker]

Rhino 1.7.14 (to be released in ~2 weeks, RC available) ships with promise support.

Async/await support is in the backlog, no eta for that one, as it's development depends on someone in the community putting in the effort.

Once 1.7.14 is released, the compile target setup for Babel can be updated to include 1.7.14, after which you should be able to use Babel to compile async/await code to promises