4 ms·

It's encouraging seeing all the work going into making tagged unions a natural part of TS. I've tried to introduce them multiple times, and have been shot down

It's encouraging seeing all the work going into making tagged unions a natural part of TS. I've tried to introduce them multiple times, and have been shot down by my team on every attempt. I think they still come across as "hacky," and more JS-minded people who are totally cool validating with if-else everywhere still can't appreciate the benefits of annotating data in this manner. I hope TS eventually arrives at a standard, low impact way to create and manipulate such structures; maybe more people will be on board then. It looks like we're moving in the right direction.

dgreensp 5y ago
Well, tagged unions, like many TS features, are designed to enable type-checking on vaguely idiomatic JS code, aren't they? That checks properties of objects in if-else statements? It sucks that people aren't open to defining their structures in a way that aids type-checking, if that's what you mean!
- jim-jim-jim 5y ago
  I understand that familiarity is TS' selling point, but that dreadful I-word was actually used against me when trying to introduce these unions. For whatever reason, some people don't find the syntax very natural at the moment. With no standard convention around the tag's name (it is `kind` in the linked PR, but I've seen it specified in many other ways), my suggestion came across like a cute self-invented gimmick rather than a fundamental concept in programming. Others had trouble differentiating the tag's literal type from a vanilla string due to the quotes. If some of the noise were eventually removed and tagged unions became true first class citizens in TS' syntax, I think some of these colleagues without as much typing experience might be more open to the idea—or at the very least understand it in the first place.
  - andrewflnr 5y ago
    I love discriminated unions, but bounced off the typescript approach because it looked like too much of a pain to actually be worth it. Hopefully features like this can make it worthwhile, because I really miss them.
  - matt_kantor 5y ago
    > my suggestion came across like a cute self-invented gimmick rather than a fundamental concept in programming Maybe the official handbook could help convince them this isn't the case: https://www.typescriptlang.org/docs/handbook/2/narrowing.html#discriminated-unions https://www.typescriptlang.org/docs/handbook/2/narrowing.htm...
goto11 5y ago
Tagged unions still require rather cumbersome JavaScript syntax to use. While the type inference support is great, much of the benefit is IMHO lost because of the syntax.

dgreensp 5y ago

Well, tagged unions, like many TS features, are designed to enable type-checking on vaguely idiomatic JS code, aren't they? That checks properties of objects in if-else statements? It sucks that people aren't open to defining their structures in a way that aids type-checking, if that's what you mean!

jim-jim-jim 5y ago
I understand that familiarity is TS' selling point, but that dreadful I-word was actually used against me when trying to introduce these unions. For whatever reason, some people don't find the syntax very natural at the moment. With no standard convention around the tag's name (it is `kind` in the linked PR, but I've seen it specified in many other ways), my suggestion came across like a cute self-invented gimmick rather than a fundamental concept in programming. Others had trouble differentiating the tag's literal type from a vanilla string due to the quotes. If some of the noise were eventually removed and tagged unions became true first class citizens in TS' syntax, I think some of these colleagues without as much typing experience might be more open to the idea—or at the very least understand it in the first place.
- andrewflnr 5y ago
  I love discriminated unions, but bounced off the typescript approach because it looked like too much of a pain to actually be worth it. Hopefully features like this can make it worthwhile, because I really miss them.
- matt_kantor 5y ago
  > my suggestion came across like a cute self-invented gimmick rather than a fundamental concept in programming Maybe the official handbook could help convince them this isn't the case: https://www.typescriptlang.org/docs/handbook/2/narrowing.html#discriminated-unions https://www.typescriptlang.org/docs/handbook/2/narrowing.htm...

goto11 5y ago

Tagged unions still require rather cumbersome JavaScript syntax to use. While the type inference support is great, much of the benefit is IMHO lost because of the syntax.