4 NEW TypeScript 5.5 Features!

[@RicoKareem]

The side-by-side, before-after demo is fire! A natural instructor.

[@codinginflow]

The filter part is amazing!

[@stuartallen2001]

If you're subscribed to web dev simplified i recommend you subscribe to @codinginflow too. Thank you both for cool tutorials 🙏

[@sourandbitter3062]

No need to add the return type "x is number" anymore. Good stuff.

[@seppo7531]

in TS 5.4 and earlier there is a `(x: unknown): x is type` syntax, so you could do const filtered = array.filter((x): x is number => x !== null) And TS would understand the filtered would be `number[]`

[@FilipeAguiarCarvalho]

That filter feature would help me a lot last month in a project for my master's degree.

[@klirmio21]

Thank you Kyle I’m a developer thanks to you

[@orelben]

Good, I was waiting for the set methods thanks

[@josuedelossantos9442]

Thank you, this is good to know!

[@ShadowVipers]

In TS 5.4 you had to use type predicates to change the array type with filter.

[@maciejzettt]

That's exactly what he presented 😅

[@Whelp_Studios_Official]

Hello Mr. Kyle, thank you for the videos you always post,most especially on Javascript ,react and react native alongside roadmaps I hope this comment reaches you cos I need guidance. I'm an aircraft engineer with embedded systems and electronics experience and them being my passion, the one thing I wish to be experienced on is web and mobile app development but all these years, I barely get anywhere in my learning, more like tutorial hell. I do hope you can guide me so I can turn my ideas into reality even if they already exist, I would love to make websites,web apps and mobile apps that are fully in my control.

[@miskaknapek]

thank you very much for a concise and very informative video!

[@playyourway2963]

thank you !

[@krtirtho]

Ecma Script adding Set in Javascript but not adding Set Operations until now is the most Brendan Eich thing to do

[@evalaviniabucur1789]

Can typescript 5.5 be used with Nextjs 14? No earlier than today I was struggling with some records from my database which I was trying to filter down to get rid of some null things and I ran into this problem :))

[@WebDevSimplified]

Yes. TS does not depend on the version of your Next.js app so you should be just fine using it with Next.js.

[@evalaviniabucur1789]

@@WebDevSimplified thank you! Yes, I know it's not dependent, but the reason I asked this question is because I work with Vercel and I was wondering if perhaps they use their own version of typescript or the version specified in my project's package.json. I didn't want to encounter build errors because of (eventually) their version.

[@seppo7531]

const filtered = array.filter((x): x is YourType => x !== null) would've done the trick

[@normanneal35]

Most of them look like "bugfixes" rather than "features" 😄

[@deucebigs9860]

Is your typescript simplified course completely free of Next.js and React? I like the theory behind Svelte so much more and am trying to learn that, which makes me realize I should get a better foundation in TS first so I don't want any react or next BS in it while I'm learning, but you seem to prefer react and next.

[@WebDevSimplified]

My TS course is entirely focused on just TS. I do have a bonus module on React included for free in the course, but it is not a part of the main course and is purely just a bonus. All the main content in the course is focused entirely on plain TS with no other library or framework.

[@deucebigs9860]

@@WebDevSimplified Awesome! I'll take a look at it when I get a chance.

[@BonaventureOnuorah]

Typescript is an advanced linter

[@MrJloa]

Cool, but im still looking forward to proposal-type-annotations and get rid of ts abstraction

[@MikeKaipis]

three!

[@mhdhasantadmori1346]

one ! ♥

[@waqasrahman1554]

I am on 5.3.3 and it is giving me no errors and type is showing number[]...even of the array is also number[] on hover

[@erin1569]

Not sponsored by regex101 I see 4:29

[@DMC888]

Adding code to fix these typescript errors is like letting the tail wag the dog. 🐕

[@user-fed-yum]

3:34 why are there semicolons at the start of each line?

[@potatoho]

Without choosing one side or the other I'll just say.. it somehow became a flex for ES developers to memorize automatic semicolon insertion rules rather than putting them at the end of lines.

[@juxuanu]

1. You could already filter by simply adding: [1,2].filter((elem): elem is number => !!elem); 3. People using Jetbrains editors already had regex linting. I wonder if tsc should really check regex. Kiss.

[@ezwtwrziehag1736]

why are you shaking ur head all the time lol

[@aryansabetnejad3886]

He tries to show that JS is so obvious & logical by shaking his head but it's already failed.

[@bundiderp5109]

Bobblehead Kyle

[@blossomcherrypink]

So you comment on it and boost his weighting in the KZbin algorithm.

[@user-888azim-97]

😁

[@user-888azim-97]

love this shaking ))

[@DiviskaAI]

Two

[@signalsensei]

four

[@Takatou__Yogiri]

Im absolute TS hater 👀.

[@JamesJansson]

Using != and not !== when talking about types is hilarious.

[@WebDevSimplified]

I almost always use != when checking for null or undefined. This is because null == undefined which means I can check for both null and undefined values at the same time. I almost never want to just check for null and not undefined.

[@JamesJansson]

@@WebDevSimplified While I get your point, this would show up as an error in Prettier because it is confusing as to whether you actually meant it. You should either be explicit about both types, or do typeof elem === 'number'

[@WebDevSimplified]

If you want my full opinion on when I use == and === I have a video talking about it. kzbin.info/www/bejne/eWa9h3Zqfa2af8k

[@josipX]

the head shaking is so alpha

[@flexairz]

5

[@gerkim62]

at 1:35 instead of typing the type of value as any why don't you type it as unknown, it seems more logical to me

[@unknownguywholovespizza]

Yes my thoughts exactly. This is a simple function so it's not an issue. But in production, I would use it to prevent using the value in an unintentional way

[@webshipon1941]

Hi three 😂😂

[@ImTheDot]

.

[@paulmurphy1144]

So filtering in TS now allows code that would also have just worked in JS years ago 😂

[@katemc516]

Wait, people still use JavaScript? 😅

[@Wentris71]

@@katemc516yeah) ant type code with JS docs 😂

[@PanicAtProduction]

These kind of logic checks make typescript extremely slower in large repos.

[@kalvikaring1304]

sorry, but i have to say, you have smart talk but your your head shaking is pretty annoying, if you can do videos without head shakes when i can watch them too without getting nervous. thank you