TypeScript 3.7

Post by svachalek » Wed, Nov 06, 2019, 5:22 AM UTC

vikingcaffiene wrote: post #109

paulddraper wrote: post #104

Earlier quoted context omitted.

&& ?. || ?? It's a shame JS at the beginning doubled down on the "billon dollar mistake" [1] with two(!) kinds of NULL instead of just using Maybe/Option. Ah well, if it were good it wouldn't be popular :/ [1] https://www.lucidchart.com/techblog/2015/08/31/the-worst-mis...

Sorry, JS? While JS might get this stuff one day, these language features are for TypeScript which is its own language. It's strongly typed and just happens to interop with and in some scenarios transpile down to JavaScript. It's whole existence is to deal with that billion dollar mistake you mentioned. Speaking of which, optional chaining and null coalescence are core language features of some very good languages. K…

Post by ajkjk » Wed, Nov 06, 2019, 6:05 AM UTC

svachalek wrote: post #111

vikingcaffiene wrote: post #109

Earlier quoted context omitted.

Sorry, JS? While JS might get this stuff one day, these language features are for TypeScript which is its own language. It's strongly typed and just happens to interop with and in some scenarios transpile down to JavaScript. It's whole existence is to deal with that billion dollar mistake you mentioned. Speaking of which, optional chaining and null coalescence are core language features of some very good languages. K…

These features are copied from TC39 proposals for JavaScript. Presumably they were deemed safe to add to TS now that they have reached Stage 3 as JS proposals. https://github.com/tc39/proposals

Post by graup » Wed, Nov 06, 2019, 6:21 AM UTC

SirensOfTitan wrote: post #36

I feel really excited about 3.7. Optional chaining and null coalescing will clean up a TON of code. ... but with that being said, 3.7 seems to have broken many aspects of the `Promise.all` interface. Right now the largest issue seems to be that if any `Promise` result in `Promise.all` is nullable, all of the results are nullable.

Post by ygra » Wed, Nov 06, 2019, 7:13 AM UTC

ajkjk wrote: post #113

svachalek wrote: post #111

Earlier quoted context omitted.

These features are copied from TC39 proposals for JavaScript. Presumably they were deemed safe to add to TS now that they have reached Stage 3 as JS proposals. https://github.com/tc39/proposals

Not so much 'copied', considering it was the TS team that has gotten them added to JS. They just didn't want to commit to anything in the TS codebase that wasn't at least stage 3 in JS.

Post by saurik » Wed, Nov 06, 2019, 7:54 AM UTC

yawaramin wrote: post #85

reggieband wrote: post #71

I'm a big fan of the new operators. One of my remaining gripes with Javascript/Typescript is the try/catch mess around await. It makes assignment of const a pain for async calls that may reject. e.g. let result: SomeType; try { result = await funcThatReturnSomeType(); } catch (err) { doSomethingWithErr(err); } // at this point result is `SomeType | undefined` if (result) { doSomething(result); } I really want some ki…

IIFEs are an option: const result = await (() => { try { return funcThatReturnSomeType(); } catch (err) { doSomethingWithErr(err); } })();

    const result = await (async () => {
      try {
        return await funcThatReturnSomeType();
      } catch (err) {
        doSomethingWithErr(err);
      }
    })();