bug#68054: [PATCH] Add tree-sitter indent rule for lexical decls in js/typescript

[Dmitry Gutov <dmitry@gutov.dev>]

On 30/12/2023 22:31, Yuan Fu wrote:
> 
>> On Dec 29, 2023, at 8:24 PM, Yuan Fu<casouri@gmail.com>  wrote:
>>
>>
>>
>>> On Dec 26, 2023, at 10:21 PM, Noah Peart<noah.v.peart@gmail.com>  wrote:
>>>
>>> Tags: patch
>>>
>>> * Bug: `js-ts-mode` and `typescript-ts-mode` are missing indentation
>>> rules for lexical declarations that span multiple lines.
>>>
>>> Recipe to reproduce:
>>>
>>> Using the following function to configure js-ts-mode and indent the
>>> buffer:
>>>
>>>     (defun try-indent ()
>>>       (interactive)
>>>       (js-ts-mode)
>>>       (setq-local indent-tabs-mode nil)
>>>       (setq-local js-indent-level 4)
>>>       (indent-region (point-min) (point-max)))
>>>
>>> Add the following example to a buffer and call `try-indent`.
>>>
>>>     let foo = 1,
>>>     bar = 2; // no indent rule matches this line
>>>
>>> No indentation is applied to the second line.
>>>
>>> This patch adds a simple indentation rules for `js-ts-mode` and
>>> `typescript-ts-mode` to handle the multi-line lexical declarations.
> It seems that js-mode indents bar to align with foo, rather than indenting one level. I feel that we should do the same, WDYT?

Yes, please. This also makes a difference when the variables are 
declared with 'const' instead of 'let'.

We should also support 'var' declarations: the parent node type to match 
against is "variable_declaration".