proposal-pattern-matching VS proposal-observable

Note, however, that there is a proposal to add pattern matching to JS.

There's an ECMAScript proposal that is in the works to add this feature to the language! It's going to look something like this.

More importantly, TypeScript typically commits to build things into itself when the proposal in JavaScript reaches Stage 3. The pattern matching proposal in JavaScript is Stage 1, but depends on many other proposals as well that may or may not need to be at Stage 3 as well for it to work. This particular proposal is interested on pattern matching on JavaScript Objects and other primitives, just like Python does with it’s native primitives. These are also dynamic types which helps in some areas, but makes it harder than others. Additionally, the JavaScript type annotations proposal needs to possibly account for this. So it’s going to be awhile. Like many years.

For true™ functional programming in JS, native pattern matching and partial function application are missing (at least for now: 1, 2). For proper OOP, it lacks real interfaces and compile-time dependency injection.

The proposal for pattern matching syntax seems more akin to what they're looking for.

https://github.com/tc39/proposal-pattern-matching

There's a proposal to add something like that to JavaScript but it's been stuck in limbo since 2017 although there are libraries like ts-pattern which implement it already.

I'll admit, it is easy to assert that the TypeScript language should not be involved in the matters of packages but I also wonder if we're moving towards a point where interfaces will be as common as namespaces and whether or not it would be sensible for the language to incorporate such type assertions into the language formally, after all, it already compiles to various forms of JavaScript and there is a stage 1 proposal submitted to the TC39 committee to give JavaScript pattern matching. If adopted, wouldn't it make sense to allow TypeScript to compile a type into a type guard for the native JavaScript pattern matcher?

Both are active tc39 proposals :)

https://github.com/tc39/proposal-pipeline-operator - Stage 2

https://github.com/tc39/proposal-pattern-matching - Stage 1

Hopefully we get both in the next couple of years.

We often add promising TC39 proposals into Civet so people can experiment without waiting.

We've added https://github.com/tc39/proposal-pipeline-operator, a variant of https://github.com/tc39/proposal-pattern-matching, a variant of https://github.com/tc39/proposal-string-dedent and others.

Since our goal is to be 99% compatible with ES we'll need to accommodate any proposals that become standard and pick up anything TC39 leaves on the table (rest parameters in any position, etc.)

https://github.com/tc39/proposal-observable

And there's the new one which seems to be getting implemented in node right now:

How does it differ from <https://github.com/tc39/proposal-observable/>?

I think it is a shame that the Observable proposal [1] still seems somewhat stuck in Stage 1. It's a better idea than just raw event emitters because of composability (if no other reason). Making Observables "first class" could go a long way to unifying a lot of reactivity patterns in various frameworks, in theory at least.

To be fair, Observables and especially Observable composition has a rough learning curve and many frameworks like Svelte intentionally prefer implict reactivity and avoiding things like explicit Observables because they are seen as too complex/"too hard" for the average developer.

(Then you get awful worst of both worlds frameworks like Angular that sort of rely on Observables but yet also don't trust teaching Observables and wind up with code that isn't properly Observable and so also has all the code for implicit reactivity and is full of nasty escape hatches that cause all sorts of composition problems and unnecessary side effects.)

[1] https://github.com/tc39/proposal-observable

Uses an interface described in the TC39 observables proposal

JavaScript doesn't have any built-in observables (addEventListener is part of the DOM API specific to browsers) though there is an old observable proposal collecting dust. I think ReactiveX (RxJS) is pretty much the go-to for any kind of observable functionality you may want. That may be a good place to start to really see what observables can do.

Observablelar streamlarga asoslangan reaktiv dasturlash paradigmasini olib kiradi JSga. Shaxsan menga eng yoqqan takliflardan biri. Bu haqida ham alohida maqola yozish niyat bor. RxJS (Angular) bilan ishlab ko'rganlar bo'lsa buni nimaligini juda yaxshi tushunishadi, endi bu library emas balki native 🚀 !!!

Observable is an object that takes a stream of data and emits events over time to react accordingly. There is a talk to add it to the ECMAScript standard and its proposal is here. Till now it is not part of the ECMAScript standard so to use it, you have to use a third-party library and the well-known Reactive Extension in Javascript is RxJs.

Well, the answer is surprisingly no. But, there is an active tc39 proposal going on around for a while, didn’t find it much active though, you could watch out here — https://github.com/tc39/proposal-observable

RxJS is an implementation of observables which do not exist natively in JavaScript. There is a proposal for adding observables to the language, but it's only stage 1 and hasn't been active for years.