Re: Promises: final steps
Kevin Smith <[email protected]>
| Newsgroups | gmane.comp.lang.javascript.ecmascript4.general,gmane.comp.web.dom.general |
|---|---|
| Message-ID | <CA+mDt2zfNTY12fr87j-nBPbS_XKUgrT1ruiQ+twY1TpL=0Thtw@mail.gmail.com> |
> Please do.
>
You're not going to like it, which will explain my hesitation : )
Think of all promises as existing in a forest, where "root" promises are
created using the Promise constructor and "child" promises are created
using `then`. Promises with [[Value]] set are green. Promises with
[[Reason]] set are red. A "checkpoint" occurs immediately after the
microtask queue has been completely flushed. At any checkpoint, any
non-root leaf nodes colored red are program errors.
This forces the programmer (me, really) to either write an error handler at
the end of a `then` chain, or to return the chain to a caller that will.
It also means that I must be strict about when error handlers are attached
to a chain. There may be important use cases that this strategy precludes
which I haven't yet considered...
{ Kevin }
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