Subject: Re: Html-like constructs fail in typescript

From: Jostein Kjønigsen <[email-masked]>
Date: Wed, 30 Nov 2022 13:59:20 +0100

On 29.11.2022 23:20, Jostein Kjønigsen wrote:
>
>> On 29 Nov 2022, at 22:48, Theodor Thornhill<[email-masked]>  wrote:
>>
>> 
>>
>>> On 29 November 2022 22:37:25 CET, "Jostein Kjønigsen"<[email-masked]>  wrote:
>>> Nice!
>>>
>>> Should we until further notice assume that js-ts-mode suffers from the same issues, and that a jsx-ts-mode might be needed too? To me it at least sounds plausible.
>> No, because there are no ambiguities in the grammar with types and jsx.
>>
> Note this behaviour was triggered even when a HTML-tag was contained inside a plain string.
>
> Even without hard typescript casts, there are places where I suspect the same issues can bleed into js-ts-mode.
>
> I’ll try to do more testing tomorrow.

First of all - good news!

Contrary to my expectations, I've tested and I cannot reproduce this 
issue in js-ts-mode.

Even more good news:

Looking deeper into this using treesit-explorer-mode (an extremely 
helpful tool, Yuan!), I found I may have misinterpreted the state of the 
parse-tree in previous report.

Based on that, I would like to revise this bug report:

  * HTML-like constructs inside strings are --/not/-- treated at
    jsx_opening_elements,
  * only angle-bracket "hard" casts (which isn't present in Javascript)
    is causing issues for fontification.

Also, reading up, from what I can tell "hard casts" using angle-brackets 
are no longer encouraged as the default way to cast:

     const service = <IService>object;

This is because the above code will cause a compiler error if used in 
TSX-files (as opposed to TS-files). Instead "as" expressions are 
preferred, because they work equally well for both TS & TSX-files:

     const service = object as IService;

That means that writing idiomatic TypeScript with typescrip-ts-mode 
should produce the expected behaviour, while one may encounter issues 
with older code.

I'm not sure introducing a new major-mode for this 1 aspect of 
TypeScript development is worth it?

Does anyone else have an opinion on this?

--
Jostein