> What should occur where the code is It would be "y" in all 3 places.
> ... is a proposal for _more_ than only getting the _name_ of an _declared_ > and _initialized_ variable? It is a proposal for getting the name of a _declared_ variable. Whether it is _initialized_ does not matter. > Should a ```RefefenceError``` _not_ be thrown simple because ```nameof``` is > used? No, an error is not thrown. ECMAScript is much more nuanced. Block scoped variables from 'let' or 'const' exist and can be *referenced* (via closure or export, currently) anywhere within the same block scope, even before they are initialized. Until they have been *initialized* (the line of code contain the declaration has been reached and evaluated), they exist in a "Temporal Dead Zone" (TDZ). Attempting to *dereference* them (i.e. access or store a value) while in this TDZ is what results in the ReferenceError. At no point does the `nameof` operator *dereference* the variable, so no error need be thrown. From: guest271314 Sent: Saturday, June 15, 4:29 PM Subject: Re: Re: What do you think about a C# 6 like nameof() expression for To: Ron Buckton Cc: es-discuss@mozilla.org What should occur where the code is ``` const x = nameof y await new Promise(resolve => setTimeout(resolve, 100000)); // should x be "y" here? await new Promise(resolve => setTimeout(resolve, 200000)); // should x be "y" here? await Promise.all([new Promise(resolve => setTimeout(resolve, 300000)), ...doStuff()]); // should x be "y" here? const y = 1; ``` ? The immediately invoked arrow function example (where a ```RefeferenceError``` is thrown) appears to demonstrate that to output the expected result of ```nameof``` within the context of the code example ``` const x = nameof y const y = 1; ``` is a proposal for _more_ than only getting the _name_ of an _declared_ and _initialized_ variable? Should a ```RefefenceError``` _not_ be thrown simple because ```nameof``` is used? On Sat, Jun 15, 2019 at 11:16 PM Ron Buckton <ron.buck...@microsoft.com<mailto:ron.buck...@microsoft.com>> wrote: ``` const x = nameof y const y = 1; ``` `x` would have the value “y”. It would not matter if `y` were initialized or had yet been reached during execution. It does not deviate from the purpose of `let` or `const`, because you are not accessing the value of the identifier. Also consider that this is legal ECMAScript in a module: ``` export { y } const y = 1; ``` The binding for `y` exists within the same block scope, it just has not yet been initialized. Exporting it via `export { y }`, closing over it via `() => y`, or accessing it via `nameof y` would all be the same. In all three cases you are accessing the *binding* of `y`, not the *value* of `y`. Even in the `() => y` case, you don’t access the *value* of `y` until you execute the function. From: guest271314 <guest271...@gmail.com<mailto:guest271...@gmail.com>> Sent: Saturday, June 15, 2019 3:57 PM To: Ron Buckton <ron.buck...@microsoft.com<mailto:ron.buck...@microsoft.com>> Cc: es-discuss@mozilla.org<mailto:es-discuss@mozilla.org> Subject: Re: Re: What do you think about a C# 6 like nameof() expression for > Sorry, I meant to say “not entirely correct”. You have not yet confirmed if in fact the expected output is referencing a variable declared using ```const``` on the current line _before_ initialization _on the next line_. That example appears to deviate from the purpose and usage of ```const```, beyond the scope of ```nameof```, and if were implemented, a ```ReferenceError``` should _not_ be thrown when a ```const``` variable that has yet to be initialized _on the next line_ is referred to _on the current line_? Aside from that example, the code which essentially already implements ```nameof``` should be able to be found in the code which implements ```ReferenceError``` relevant to ```const```. On Sat, Jun 15, 2019 at 10:47 PM Ron Buckton <ron.buck...@microsoft.com<mailto:ron.buck...@microsoft.com>> wrote: Sorry, I meant to say “not entirely correct”. From: Ron Buckton Sent: Saturday, June 15, 2019 3:03 PM To: guest271314 <guest271...@gmail.com<mailto:guest271...@gmail.com>> Cc: es-discuss@mozilla.org<mailto:es-discuss@mozilla.org> Subject: RE: Re: What do you think about a C# 6 like nameof() expression for > At that point in the example code the identifer ```y``` does not exist. That is not entirely incorrect. The identifier `y` exists, but its binding has not been initialized, otherwise you couldn’t refer to y in this case:
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