As someone noticed already, the operator should be called eventually "mouse" operator, as mice is plural and was a misunderstand of mine 😅
On Fri, Sep 6, 2019, 00:54 Andrea Giammarchi <[email protected]> wrote: > Since somebody asked me already elsewhere about the expected precedence of > the operator, this would be my answer: > > ```js > const result = await dbQuery(data)<?.rows; > ``` > > would be the equivalent of > > ```js > let result = await dbQuery(data); > if (result != null && result.rows != null) > result = result.rows; > ``` > > or to better answer about precedence: > > ```js > const result = (await dbQuery(data))<?.rows; > ``` > > I hope this adds some extra context to this proposal. > > > On Fri, Sep 6, 2019 at 12:28 AM Andrea Giammarchi < > [email protected]> wrote: > >> absolutely, I'm working with PostgreSQL these days and indeed for any >> promise/awaited result this pattern looks like a win, and while it's >> targeting a limitation of the chaining one, it can be used in various other >> cases where knowing the initial result is more important than just falling >> back to "_dunnoWhatHappenedThere_" >> >> On Fri, Sep 6, 2019 at 12:24 AM Michael Luder-Rosefield < >> [email protected]> wrote: >> >>> Another pattern it could be useful in is with, say, nosql dbs where >>> something might be an object or id reference: >>> >>> ``` >>> const fooId = foo<?.id; >>> ``` >>> >>> On Thu, 5 Sep 2019, 23:03 Andrea Giammarchi, < >>> [email protected]> wrote: >>> >>>> Another use case that I believe will be common is the following one: >>>> >>>> ```js >>>> // current state of the art >>>> const result = dbQuery(data)?.rows ?? 'did it just failed or what?'; >>>> >>>> // VS the "mice operator" >>>> const result = dbQuery(data)<?.rows; >>>> >>>> // if it was rows >>>> if (Array.isArray(result)) >>>> console.log(result); >>>> else if (result instanceof Error) >>>> console.error(result.message); >>>> else >>>> console.warn(`unexpected result: ${result}`); >>>> ``` >>>> >>>> Ideally, the "mice" should grant chaining up to its latest presence, >>>> but I wouldn't know right now how to reference to it ... >>>> >>>> ```js >>>> // if no ?? is needed, this might work >>>> const result = dbQuery(data)<?.rows?.data?.entry; >>>> >>>> // if ?? is needed, no idea how to back-reference the latest >>>> successfull "mice" result >>>> ``` >>>> >>>> >>>> >>>> >>>> On Thu, Sep 5, 2019 at 11:44 PM Tab Atkins Jr. <[email protected]> >>>> wrote: >>>> >>>>> On Thu, Sep 5, 2019 at 2:39 PM Andrea Giammarchi >>>>> <[email protected]> wrote: >>>>> > >>>>> > This is basically a solution to a common problem we have these days, >>>>> where modules published in the wild might have a `default` property, to >>>>> support ESM logic, or not. >>>>> > >>>>> > ```js >>>>> > // current optional chaining logic >>>>> > const imported = exported?.default ?? exported; >>>>> > >>>>> > // my "mice operator" proposal >>>>> > const imported = exported<?.default; >>>>> > ``` >>>>> > >>>>> > Semantically speaking, not only `<?` actually looks like a mice, it >>>>> also points at its previous value in case the chaining didn't work. >>>>> > >>>>> > Beside the basic example, the "mice operator" might save CPU cycles >>>>> when it comes to involving more complex expressions, i.e. >>>>> > >>>>> > ```js >>>>> > // current "solution" >>>>> > const thing = require('thing')?.default ?? require('thing'); >>>>> > >>>>> > // mice operator >>>>> > const thing = require('thing')<?.default; >>>>> > ``` >>>>> > >>>>> > This is also easily tranpilable, so kinda a no-brainer for modern >>>>> dev tools to bring in. >>>>> > >>>>> > TL;DR specially for cases where an accessed property should fallback >>>>> to its source, this operator might save both typing and CPU time whenever >>>>> it's needed. >>>>> >>>>> I find it a rather curious pattern, that I'd never seen before! Is it >>>>> used in anything besides this ESM-compat thing you're talking about? >>>>> >>>>> (Saving CPU cycles is not a convincing argument; it's trivial to write >>>>> such a line over two declarations and avoid any expensive >>>>> recomputations.) >>>>> >>>>> ~TJ >>>>> >>>> _______________________________________________ >>>> es-discuss mailing list >>>> [email protected] >>>> https://mail.mozilla.org/listinfo/es-discuss >>>> >>>
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