PostMessage without serialization

[Elephmoon]

Resolve #897
I searched through the files in the frontend, in all places where I found postMessage removed unnecessary serialization.
Also, I think if we haven't stringify, then we don't need to check for string type here.

remark42/frontend/app/components/root/root.tsx

Line 187 in 553bcf2

const data = typeof event.data === 'string' ? JSON.parse(event.data) : event.data;

[codecov]

Codecov Report

Merging #903 (54679a2) into master (6d4be02) will increase coverage by 0.00%.
The diff coverage is 3.84%.

@@           Coverage Diff           @@
##           master     #903   +/-   ##
=======================================
  Coverage   43.98%   43.99%           
=======================================
  Files         127      127           
  Lines        2903     2905    +2     
  Branches      662      656    -6     
=======================================
+ Hits         1277     1278    +1     
- Misses       1613     1614    +1     
  Partials       13       13           

Impacted Files	Coverage Δ
frontend/app/common/types.ts	100.00% <ø> (ø)
frontend/app/common/user-info-settings.ts	0.00% <ø> (ø)
frontend/app/components/auth-panel/auth-panel.tsx	78.16% <0.00%> (-0.91%)	⬇️
frontend/app/components/root/root.tsx	0.00% <0.00%> (ø)
frontend/app/embed.ts	0.00% <0.00%> (ø)
frontend/app/utils/postMessage.ts	0.00% <0.00%> (ø)
frontend/app/components/dropdown/dropdown.tsx	25.25% <20.00%> (+0.76%)	⬆️

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[akellbl4]

Also, I think if we haven't stringify, then we don't need to check for string type here.

Yes, it's a good point, but for example, in dev, webpack could send string inside post message data.
In my opinion, we should drop JSON.parse for data from postMessage and process message if it's an object.
Good to add these changes in current PR.

[Elephmoon]

we should drop JSON.parse for data from postMessage

I'm not very good in typescript and I can't catch how to make it.
@akellbl4 can you help me?

remark42/frontend/app/components/root/root.tsx

Line 187 in 553bcf2

const data = typeof event.data === 'string' ? JSON.parse(event.data) : event.data;

In this line JSON.parse implicitly changing type to any and in next line we can get data.theme.
If I remove JSON.parse data type will not change and we will not get data.theme.
I need to define type with Theme type or what is the best way in this situation?

[akellbl4]

@Elephmoon we already removed JSON.stringify on sending. It means we will receive JS object.
All we need to check if data is an object and work with it. Just like that:

onMessage(event: MessageEvent<{ theme?: string }>) {
    const isObject = typeof event.data === 'object' && event.data !== null && !Array.isArray(event.data)
    if (!isObject) {
        return
   }
   // work with data
}

We set MessageEvent type to the event and wait for { theme?: string }. We don't sure what we will get because we add such check on evt.data
I don't like the way how it's should be checked but it's js. @Mavrin maybe you know cool methods to do that?

[akellbl4]

@Elephmoon we have the same data processing from post message in embed.ts and other places.

remark42/frontend/templates/iframe.ejs

Line 141 in 345ee88

const data = typeof event.data === 'string' ? JSON.parse(event.data) : event.data;

remark42/frontend/app/embed.ts

Line 268 in 345ee88

const data = typeof event.data === 'string' ? JSON.parse(event.data) : event.data;

remark42/frontend/app/components/dropdown/dropdown.tsx

Line 138 in e1e8da4

const data = typeof e.data === 'string' ? JSON.parse(e.data) : e.data;

[akellbl4]

Sorry for the long response.
Thank you for your contribution!

[akellbl4]

@Mavrin could you please review the PR? I've added some additional code, could be cool to have second opinion on it :)

[Mavrin]

lgtm

[umputun]

@Elephmoon can you rebase all of this into a single commit so I could merge it nicely?

[akellbl4]

@Elephmoon hi, do you need help with it?

[Elephmoon]

@Elephmoon hi, do you need help with it?

Sorry. I’m moving to other city right now, I believe that I have time today evening and I will solve it

[Elephmoon]

Ugh. I made incorrect rebase and lost all changes (;

[akellbl4]

@Elephmoon I'll try to revert it ;)

[akellbl4]

@Elephmoon I've fixed it, Is it okay for you to merge it with squash?

[Elephmoon]

Yep. I squashed it

[akellbl4]

@umputun good to merge ;)