Symbol.toStringTag can be used for this purpose now (and it already unfortunately destroyed the reliability of `Object.prototype.toString.call`).
On Tue, Jan 15, 2019 at 3:07 PM Randy Buchholz <[email protected]> wrote: > My thought was Symbol.typeof could improve both reliability and > flexibility. It could be abused, but no more than Symbol.toStringTag. My > use case is putting classes into “namespaces”. With [Symbol.typeof] = > “Collections.Lists.LinkedList”, I can get the qualified type of the object. > I can also use this in my IDE to keep my classes organized if I write tools > to help me. Since imports use paths, if I move a file refactoring can be > painful. With an IDE extension, I can trigger an event when I move a file > to prompt “Update all imports?”. It can parse my project and update all > imports to point to the right place. > > > > *From:* es-discuss <[email protected]> * On Behalf Of *Jordan > Harband > *Sent:* Tuesday, January 15, 2019 3:36 PM > *To:* J Decker <[email protected]> > *Cc:* [email protected] > *Subject:* Re: Proposal: Symbol Linked to `typeof` > > > > `.constructor` is unreliable, and can be easily forged - of course, > `Symbol.typeof` would create the same unreliability with one of the few > truly reliable operators in the language. > > > > On Tue, Jan 15, 2019 at 12:38 PM J Decker <[email protected]> wrote: > > > > > > On Sat, Jan 12, 2019 at 8:19 AM Randy Buchholz <[email protected]> > wrote: > > (Hi all, new to group) > > > > Some of the Well Known Symbols are linked to standard functions – > Symbol.toStringTag - A string value used for the default description of an > object. Used by Object.prototype.toString(). > > > > When I have a Class instance (say, `const flow = new Flow()`, the > debugger shows `flow = Flow {`. > > But when I do `console.log( typeof flow)` the output is `object`. > > > > I assume changing basic behavior `typeof` would be breaking, but extending > it through a symbol would be useful. > > > > `Symbol.typeofTag` of just `Symbol.typeof` > > > > Invoking `typeof` on an object with this symbol would return “user-typed” > information. > > > > > > can't you just use the constructor name when needing more detail? > > > > var a = new Date(); > > a.constructor.name > > "Date" > > > > > > (Posting Question) > > What is the preferred format/approach for highlighting code in posts? > > ____________________ > > Possible Approaches > > ``` > > class Flow { > > get [Symbol.typeof]() { return Flow; } or { return “Flow” } > > } > > ``` > > would work much like Symbol.species. Implicitly casting to string would > be more intuitive I think. > > > > Other approaches, (special handling of well-knowns) could be: > > > > Decorator-ish > > ``` > > [Symbol.typeof] = “Flow” > > Class Flow {… > > ``` > > or inferred > > > > ``` > > [Symbol.typeof] > > class Flow {… > > ``` > > > > Internal – In class, but not in a function. > > > > ``` > > Class Flow { > > [Symbol.typeof] > > or > > [Symbol.typeof] = “Flow” > > or > > [Symbol.typeof] = Flow > > or > > [Symbol.typeof] = this > > > > ``` > > > > Constructor > > ``` > > Class Flow { > > Constructor() { > > this[Symbol.typeof] = … > > … > > ``` > > > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss >
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