On Fri, Oct 14, 2016 at 9:05 AM Brian Ninni <ninni.br...@gmail.com> wrote:
> I did a quick search and didn't find any recent mentions of this topic. > > On more than one occasion I've had to determine whether something was a > plain old Object, or some other class. This involves checking that the > given object was NOT an instanceof any other acceptable class. > > Array, RegExp, Function, and Class Literals all already create an Object > sub-class, so why not Object Literals? > Terminology clarification: "Object literal" refers to the syntactic grammar definition. > It doesn't have to operate any differently than a standard Object does > (though it allows room for deviation in the future), just have a different > constructor so it can easily be determined whether it is a literal or not. > > This would break code that uses `obj.constructor === Object`, but that > code is not always reliable since the 'constructor' property can be > overwritten without any side-effects anyway. > > Are there any other major reasons why this is a bad idea? > Objects created by `new Object()`, `Object()`, `let/const/var o = {}` are functionally equivalent*—changing the runtime semantics of only the syntactic form would be a web-breaking change. * Follow: - https://tc39.github.io/ecma262/#sec-object-value - https://tc39.github.io/ecma262/#sec-ordinarycreatefromconstructor - https://tc39.github.io/ecma262/#sec-object-initializer-runtime-semantics-evaluation Rick > >
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