Unify posts & markdown rendering on desktop and mobile

[ghost]

Mobile version and desktop version doesn't have the same rendering of posts and comments.
Till then the following differences have been detected :

• a double-space plus a return provoque a simple return on desktop and a line break on mobile, Replace pagedown by markdown-it #5526
• <del> tag arn't rendered on mobile and are rendered as text seems like <del> tag aren't rendered at all with Replace pagedown by markdown-it #5526. Related to [Markdown] Bad parsing of <, > and & in code #5569
• strange emphases formating aren't rendered the same way ; e.g : w**or**rd (see here for an example):

• code rendering fails on mobile for inline highlight (see above, related to Consistent styling for code tags #4575 and Code block overflows page on mobile #5586)

[Flaburgan]

We should simply use the same method to parse markdown in both mobile and desktop views.

[Raven24]

I don't know if that's feasible. Desktop is rendered by JS while mobile gets rendered on the server.
JS might be too intensive for mobile devices while rendering on the server has a negative impact on the speed of the desktop version.

I think we could instead have a formal test-suite of "our" markdown behaviour and let both renderers run against it to make sure they produce the same output.

[jhass]

Let's revisit this after #5457 is resolved.

[ghost]

JS might be too intensive for mobile devices while rendering on the server has a negative impact on the speed of the desktop version.

I really think we can greatly speed up by deactivating useless JS animation, e.g : the sliding to display the menu. Also, there are some thing that currently need connexion on mobile, e.g display the comment area when clincking on the button "comment". It fails when there's no connexion and eventually dispays the area several times.

Numerous things can be improved on mobile version.

[Flaburgan]

e.g : the sliding to display the menu

The transition is done in pure CSS and is rendered by the GPU (at least with a gecko based rendered engine). There is almost no JS in the mobile view. I agree that a lot of things can be improved, and maybe speed is one, but it is not that bad.

[ghost]

Nope, not that bad, but just many many little ugly bugs everywhere. :/
Well, not everywhere but... Well you understood me !

[polsvoice]

@Raven24 Maybe I could look at the JavaScript, run some tests, and see if there's any way to optimize it for mobile? Just a thought.

[Raven24]

I still think rendering on the server side for mobile is a good strategy, to be honest

[polsvoice]

@Raven24 I'm curious why you think so.

[Fensterbank]

Hi,

I found a problem with my post today, which seems pretty related to this issue:
https://pod.geraspora.de/posts/3840898

I have a literal </div> in my post content, which is visible in desktop view, but not existing in the mobile view.

I thought it could be a escaping problem, but the </div> has definiteley been removed by server side code. :-(