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What's new in ES2022? 🤔

Jasmin Virdi on March 05, 2022

Soon the new version of ECMA Script will become standard in few months. So let's take a glimpse at the features that will be part of ES2022. ...

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Baraa Baba • Mar 6 '22

I will miss arr[arr.Length -2]

Jasmin Virdi • Mar 6 '22

True 😅

Massimo Artizzu • Mar 10 '22

... or not! 😅

Anna R Dunster • Apr 2 '22

Don't worry, you can still use it if you want ;)

Blessing Hirwa • Mar 11 '22

I didn't like this one. It could mislead me sometimes 😂/

Adnane Chaikhi • Mar 14 '22

hhhhhhhhhhhhhhhhh

Mohamed ID-ABDELLAH • Jan 30

so true hahahahah

🚩 Atul Prajapati 🇮🇳 • Mar 6 '22

Ohh wow

Jasmin Virdi • Mar 6 '22

Thanks👍

Rasmus Schultz • Mar 7 '22

What is error.cause for?

Normally, the cause of the error is what I would put in the error message. I mean, what else would you put there?

Why do we need another field for that?

I don't know of any other language that has two text messages in the same exception. What for? 🤷‍♂️

Alex Bea • Mar 7 '22

The error message might sometimes be used for a public-facing message. You could then put more technical information in the cause as well. That's my guess, at least.

Rasmus Schultz • Mar 7 '22

Ah, mystery solved!

2ality.com/2021/06/error-cause.html

It's for chaining errors - like the "inner exception" you have in many other languages.

Because you can throw anything in JS, the property type isn't specified as Error - but the intention is similar.

Jasmin Virdi • Mar 7 '22

Thanks for attaching this link for reference. 🙂

The way this would be super helpful is in deeply nested functions with chained errors.
Like if we have mutiple try catch block inside a deeply nested function so we pass the string as the purpose of that block and cause as the argument of catch block. For example:

function deeplyNested() {
  try {
    // outer block logic.

    let appData = [{...}]
    // app data array parsing.
    appData.map(
      (data) => {
        try {
          // ···
        } catch (error) {
          throw new Error(`While processing ${data}`, {
            cause: error
          });
        }
      });
  } catch (error) {
    throw Error('Error while processing outer block', {
      cause: error
    });
  }
}

Rasmus Schultz • Mar 7 '22

That sounds unlikely?

At least, I've never heard of anyone using exceptions for display purposes - exceptions generally do contain technical information, they are usually intended for developers, not for users. How would you deal with localization, for instance... That's just not what exceptions are for...

Juvenal PENGELE • Mar 8 '22 • Edited

I may be wrong but I do not think this is correct "For static data we have Static fields and Static Blocks that are executed every time a new instance is created.".

Static blocks are evaluated once during Class definition not every time a new instance is created.
When a new instance is created, it is the code in the construction that is executed.

Jasmin Virdi • Mar 8 '22 • Edited

Yes you are right, static blocks are executed when a class is created not in case of instance. Updated the statement.

Thanks👍

Brett Zamir • Mar 6 '22

Informative post, thank you. There is apparently an error in the output listed for matchObj.indices.groups however which should instead by an object keyed by group.

Jasmin Virdi • Mar 7 '22

Hey,

Actually, I included the full output which is an array having an object keyed by group.

I should’ve included just the groups output for more clarity.
Thanks for pointing out buddy!😀👍

Brett Zamir • Mar 7 '22

This is what I see as the output showing on the page:

matchObj.indices.groups;
/*
Output -
[0,4]
*/

There's no object showing there...

Jasmin Virdi • Mar 7 '22 • Edited

I was referring to the snippet just above this one 😅
I should’ve returned the full object instead of returning just the indices.

Updated the post. Thanks 👍

Conner Ow • Mar 7 '22

Top-level await is what I've been waiting for forever!!

Can't wait for these to come out!!

sanidz • Mar 8 '22 • Edited

flatMap operator is alternative but sure its nice to have

Mike Bybee • Mar 7 '22

I'm very excited for being able to use the top level await examples you gave (minus the lodash part).

Jasmin Virdi • Mar 7 '22

😁

Jim Aho • Mar 23 '22

Can you give an example as of why?

/ C# dude here

Mateusz Skrobiś • Mar 7 '22

superb post, thanks.

Jasmin Virdi • Mar 7 '22

🙂

SeongKuk Han • Mar 7 '22

Thank you for sharing the post. :)

Jasmin Virdi • Mar 7 '22

🙂

Sahan • Mar 7 '22

Thanks for the breakdown. Nicely written too 👏

Jasmin Virdi • Mar 7 '22

Thanks👍

Akash • May 28 '23

Short and crisp. Thumbs up for that but one minor feedback though, it would have been great if practical/possible use cases around it would have been shown or told on top of the syntax. Cheers!

Jasmin Virdi • May 28 '23 • Edited

Thanks for sharing the feedback. Will definitely work on it. 🙌

John Peters • Mar 6 '22

Excellent summary Tx.

Jasmin Virdi • Mar 6 '22

Thank you! 👍🏻

Steveplays • Mar 6 '22

Great post Jasmin! Very informative.

Jasmin Virdi • Mar 6 '22

Thank you! 👍

Saad BENBOUZID • Mar 11 '22

Laughing in typescript

(JK, very interesting !)

qq449245884 • Mar 8 '22

Dear Jasmin Virdi，may I translate your all dev articles into Chinese?I would like to share it with more developers in China. I will give the original author and original source.