Promise methods

[sashafirsov]

CssChain elements could have members/methods to return own status as a Promise object.

There is series of patterns of multiple promise use reflected in promise helper API:

• Promise.all()
• Promise.any()
• Promise.allSettled()

Proposed
.promiseAll(), .promiseAny(), .promiseAllSettled() to return the Promise object which would be resolved on each array element promise member or element as a Promise.

Signatures

• .promiseAll() - array element promise member or element as a Promise.
• .promiseAll( propName ) - element property with given name
• .promiseAll( el=>Promise ) - callback on each element which returns a promise

If elements of $var CssChain have a promise API, following is identical:

await Promise.all( $var );
await $var.promiseAll();
await $var.promiseAll( el=>el.promise ); // when element has a promise property