| 21 Jan 2020 |
| 01:47:50 |  Keith Layne (Gitter) | Then it becomes nominal |
| 01:49:00 |  Tushar Mathur (Gitter) | what's the intuition around having only structural typing for classes |
| 01:49:33 | Keith Layne (Gitter) | Are you asking why? Or how to develop intuition about structural types? |
| 01:49:44 | Tushar Mathur (Gitter) | "why" |
| 01:50:22 | Keith Layne (Gitter) | Cause Anders says so? I don't know. It was a design decision. |
| 01:50:31 | Tushar Mathur (Gitter) | :D |
| 01:50:39 | Tushar Mathur (Gitter) | even for classes? |
| 01:50:57 | Tushar Mathur (Gitter) | that can cause bugs in the program. |
| 01:51:54 | Keith Layne (Gitter) | The class is a function. The value A is the constuctor. The type A is the interface that the constructor returns. So the interfaces A and B in your example are indistinguishable. |
| 01:53:19 | Keith Layne (Gitter) | So I'd say "it can cause bugs" is a result of not understanding or misusing the language. Which is not a criticism of you or anybody. It's just that TS is different than other languages, and blindly following the same patters absolutely can cause bugs. |
| 01:53:40 | Keith Layne (Gitter) | (edited) ... same patters absolutely ... => ... same patterns absolutely ... |
| 01:54:06 | Tushar Mathur (Gitter) | Adding a private property is a hack. |
| 01:54:51 | Keith Layne (Gitter) | If you say so. But you want nominal types in a language that's structurally typed, so it's not that surprising that it requires a hack. |
| 01:55:15 | Tushar Mathur (Gitter) | hmm .... that makes sense. |
| 01:57:31 | Keith Layne (Gitter) | There are maybe a couple other ways to get effectively nominal types, but I don't remember offhand. You can probably search "nominal" and find lots of results in the TS repo. |
| 01:58:26 | Tushar Mathur (Gitter) | class A {
constructor(readonly name: string) {}
}
class B {
constructor(readonly name: string) {}
}
function foo(a: A): void {
if (a instanceof A) {
// I feel silly, putting this check here
}
}
foo(new B(''))
|
| 02:01:30 | Keith Layne (Gitter) | yeah the key there is that A has different meanings in those two positions. But I get what you mean. |
| 02:05:38 | Tushar Mathur (Gitter) | Also for me the problem is that I don't control over the code of A so I can not go and add the private property as you suggested. |
| 02:05:52 | Tushar Mathur (Gitter) | (edited) ... property asyou ... => ... property you ... |
| 02:07:42 | Tushar Mathur (Gitter) | apparently flow as a solution : https://flow.org/en/docs/lang/nominal-structural/#toc-nominal-typing |
| 02:50:59 | |  Nathima (Gitter) joined the room. |
| 02:51:00 | Nathima (Gitter) | Hey team, I am trying to do some cleanup of my typescript implementation, so I'm hoping for some clarify points. In the tsconfig.json are typeRoots and types mutually exclusive? Documentation has some weird stess points. It mentions states that using typeRoots disables @types, while using types also disables @types, but they do not mention disabling each other. I am trying to use types to include certain packages, and then use a typesRoots within my own package so that I don't need to do things like /// <reference types="../types" /> in all of my files. Is it possible to have TS globally import my reference? |
| 02:53:50 | Nathima (Gitter) | My next question, is that even if I include my /// <refrence />, my JSDoc is not appearing in my IDE (intelliJ). It just shows as No documentation found., despite having clear /** .. */ documentation defined. Is there a flag that I am missing that will enable this? |
| 04:48:22 |  AnyhowStep (Gitter) | @tusharmath you're not the first to bring it up. The TS issues page has a bunch of issues opened with people asking the behavior be changed. However, it's probably too late to do so. |
| 04:48:25 | AnyhowStep (Gitter) | Also, a lot of JS is structurally typed. |
| 04:48:41 | Tushar Mathur (Gitter) | @AnyhowStep Yes. |
| 04:49:02 | AnyhowStep (Gitter) | Like promises. Returning { then : "hi" } inside a promise causes errors, IIRC |
| 05:39:18 |  Simo Moujami (Gitter) | Hello, anyone familiar with ts-node-dev? I added a script command to package.json to transpile typescript and watch for file changes: "dev": "ts-node-dev --respawn --transpileOnly --project tsconfig.server.json ./server/index.ts",
The server starts fine but file changes are not detected. If on the other hand I change a file in the output folder build/, then tsnd detects the change there, but not in the source directory |
| 05:39:31 | Simo Moujami (Gitter) | (edited) ... ```
"dev": "ts-node-dev ... => ... ```
"dev": "ts-node-dev ... |
| 05:39:54 | Simo Moujami (Gitter) | (edited) ... If on the other handI ... => ... If I ... |
