Why ES6 introduced classes yet `Symbol` not to be used with `new`?
andrea.giammarchi at gmail.com
Mon Aug 15 21:28:16 UTC 2016
`Symbol.create()` together with others `Symbol.for()` and company would've
been a "least surprise" choice with a `Symbol` spec'd like `Math`, `JSON`
or other global objects ... but yeah, we have a precedent now, so I guess
in the future will be like that.
On Mon, Aug 15, 2016 at 7:20 PM, Allen Wirfs-Brock <allen at wirfs-brock.com>
> > On Aug 15, 2016, at 1:27 AM, Andrea Giammarchi <
> andrea.giammarchi at gmail.com> wrote:
> > FWIW, if `Object(Symbol()) instanceof Symbol` is true, and it is, we can
> say `Symbol` is just an anomaly in the specs because it acts like other
> primitive constructors but it throws if used as `new Symbol()`.
> > Developers that would've written `new Symbol` are the same that write
> `new Boolean` or `new Number` and `new String`.
> > If these people don't put minimal effort to better learn/use the
> programming language I wonder why the rest of the entire community should
> be penalised with "quirks" like `Symbol` is.
> The difference is that unlike Number/String/Boolean, there is not a
> literal syntax for creating Symbol values. For those primitive types that
> have a literal representation, it is very rare to ever need to explicitly
> instantiate a wrapper object via `new` and hence the there is little chance
> confusing the designation of a primitive value with instantiating a wrapper.
> Because Symbol does not have a syntactic literal form, some sort of
> invocation is required to acquire a new unique primitive Symbol value.
> That is where you get the potential for confusion between `Symbol()` and
> `new Symbol()`. And minimizing this sort of mistake is not just a matter
> of needing “better learning”. Even an experts can have momentary mental
> slips and type a `new Symbol()` when they really meant `Symbol()`.
> In the future, I would expect any new primitive types that have literals
> to follow the precedent of Number/String/Boolean and any that do not to
> follow the precedent of Symbol.
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