airbnb/javascript

JavaScript Style Guide

sgda021992

@sgda021992

can anyone tell me how can i achieve this

Ashokkumar

@Ashokkumar93

Hi
Using moment js how to get the current time of specific time zone in browser.
For suppose I’m in Singapore time zone, but I want to get current time of America/Los_Angeles.
Can some one helps me. Thanks

Jordan Harband

@ljharb

this isn't a general JS help channel, it's for airbnb's javascript style guide.

Shrugsy

@Shrugsy

Can anyone please explain this part of the airbnb style guide to me?
https://github.com/airbnb/javascript#arrays--mapping
It says:

4.6 Use Array.from instead of spread ... for mapping over iterables, because it avoids creating an intermediate array.

// bad
const baz = [...foo].map(bar);

// good
const baz = Array.from(foo, bar);

But I don't understand why you wouldn't instead do:

const baz = foo.map(bar);

I think I might understand it now. If it's already an array, foo.map(bar) is fine. If it's a non-array iterable, then use Array.from to prevent converting to an array just to use map

Jordan Harband

@ljharb

yep, that's right

Shrugsy

@Shrugsy

Is this still accurate?: https://github.com/airbnb/javascript#generators--nope

11.2 Don’t use generators for now.

Why? They don’t transpile well to ES5.

Jordan Harband

@ljharb

it's not well explained, but yes

generators transpile to need regenerator-runtime

which is slow and heavyweight

(and there's not many real use cases for generators anyways ime)

Shrugsy

@Shrugsy

Thanks, appreciate the extra info

Shrugsy

@Shrugsy

Are there plans for the React portion of the guide to be updated further? Given the way it refers to function components as stateless and only recommending them if you don't have state or refs, I feel like it hasn't been updated to reflect the introduction of hooks
https://github.com/airbnb/javascript/tree/master/react#class-vs-reactcreateclass-vs-stateless

Jordan Harband

@ljharb

it has indeed not been updated for that

Richard Sithole

@Sliqric7053

Hi there

I have an async function which I would like to convert to an Observable stream (using rxjs operators). The await calls must execute in the order they appear in the function.

async authenticateUser(profile: Profile): Promise<any> { 
  let authCookie: any;  

   try { 
         authCookie = await getCookie(); 
    } catch (error) { 
           console.error(error); 
     }  

   if (!authCookie || authCookie?.length < 1) { 
            cancelAuthenticationCookieGet(); 
            throw {message: "login failed", status: -2}; 
      }

    await saveProfileAsync(profile);  

    await storeCurrentAuthCookieAsync(authCookie); 

    storeSessionStorage();  

    await setPartitionSessionCookie(profile.url, authCookie); 
}

Is there a clean way to accomplish the above?

Mile Mijatović

@mijatovicmile

I have one JavaScript specific question

If we have an array of 5 numbers, and the task is to pack their binary values into a single integer

How to do that , any solution for that?

Jordan Harband

@ljharb

this isn't a general js help channel, it's for airbnb's javascript styleguide.

Mile Mijatović

@mijatovicmile

Ok, never mind

Do you have an idea how to solve that ?

Jordan Harband

@ljharb

i don't know what you mean by "binary values"

are they all of fixed width?

Mile Mijatović

@mijatovicmile

@ljharb Why enzyme ?

I saw that you are contributor

description is :

Enzyme is a JavaScript Testing utility for React that makes it easier to test your React Components' output. You can also manipulate, traverse, and in some ways simulate runtime given the output.

Why we can't do that with just jest

too many yarn or npm packages can lead to enormous bundle size

Jordan Harband

@ljharb

jest is a test runner. Enzyme is a react testing library. You can use any test runner, but you have to use one - and none of them let you test react

and bundle size is irrelevant for tests

Mile Mijatović

@mijatovicmile

Yes, I understand

But I have one issue, because I created app with yarn create react-app ... and by default I got setupTests.js file with import '@testing-library/jest-dom/extend-expect';

I deleted all three default @testing-library... packages

I am not sure how to set up setupTests.js file according to the enzyme test runner instead of default @testing-library...

any advice will be appreciate

Jordan Harband

@ljharb

react-testing-library and enzyme are both react testing libraries. you'd need one or both, combined with something like jest

enzyme's repo has docs with a jest setup guide

Mile Mijatović

@mijatovicmile

Thank you

Bhargav yadati

@bhargavdt3

Any idea, How to get a left position of an element which is in iframe, and both iframe and parent document bodys are set with zoom : 1.2 and zoom 0.9

Vyacheslav

@Voronenko

s4cr

@s4cr

hello

Shao Chenyang

@tzsword

Do facebook, Google or some other “big” companies use Domain Driven Design principles developing their applications?

tuerfight

@tuerfight

Is there a way to write dynamic form in play(scala) without using React(or teah like that) just use normal html and js (if possible not use @helper)? For example, a form to let user write setting for servers, we don' t know how many settings they will make so we use a

Form(serversetting:List[ServerSetting])     serversetting->list(mapping(id->number,purpose->Text)(ServerSetting.apply)(ServerSetting.unapply))

data structure. In this case, what is the best way to write the html code?

available12

@available12

hello guys i need help..I have a bot Mod for my stream..he is always on in the vps ...there is any way to make the bot join only if steam on..and leave automaticly if it off...is that possible, please help

Ali Torki

@ali-master

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