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This is not TypeScript-specific, it’s a stage-3 ECMA-262 proposal. https://github.com/tc39/proposal-explicit-resource-management/ https://github.com/tc39/propo

This is not TypeScript-specific, it’s a stage-3 ECMA-262 proposal. https://github.com/tc39/proposal-explicit-resource-management/ https://github.com/tc39/proposal-explicit-resource-managemen... It’s a shame the author insisted on it looking like C# and sabotaged attempts to combine disposal with destructuring. Also, there is no move operator without futzing around with DisposableStack. Though that could be introduced later; it’s not a day-zero design issue.

ignoramous 3y ago
TFA mentions as much: TypeScript 5.2 will introduce a new keyword - 'using' - that you can use to dispose of anything with a Symbol.dispose function when it leaves scope. This is based on the TC39 proposal, which recently reached Stage 3, indicating that it is coming to JavaScript.
- paraboul 3y ago
  Agreed with OP, the title is misleading. Typescript technically doesn't introduce any new runtime feature. This is basically a polyfill for an upcoming Javascript feature.
- franciscop 3y ago
  No, I am very familiar with JS and wasn't sure reading the article what bits were the new TC39 proposal and what bits were TS-specific. It seems, from having read it once quickly, that it's just TS adding support early to a feature that will come in JS, similar to how you could add support to async/await in your transpiler before they were commonplace by transforming them into promises back in the day. But that's definitely not a "TS new keyword".
Dylan16807 3y ago
From a brief search, it looks like the semantics around destructuring and what exactly gets disposed were causing confusion? What's the not-C#-like method that would have allowed destructuring in a better way?
hn_throwaway_99 3y ago
> and sabotaged attempts to combine disposal with destructuring. Can you explain by what you mean by this? What would "disposal combined with destructuring" look like?
potsandpans 3y ago
this happens a lot in tc39 proposals unfortunately.
scarab92 3y ago
The overwhelming share of improvements made to Java, Javascript, Typescript etc over the past decade have been inspired by C#, so I can understand why the C# terminology was front of mind. Can you elaborate more of what combining disposal and destructuring would look like?
- vips7L 3y ago
  I’m not sure Java has taken anything from C#. Most of its recent features have been taken from ML influences.

ignoramous 3y ago

TFA mentions as much: TypeScript 5.2 will introduce a new keyword - 'using' - that you can use to dispose of anything with a Symbol.dispose function when it leaves scope. This is based on the TC39 proposal, which recently reached Stage 3, indicating that it is coming to JavaScript.

paraboul 3y ago
Agreed with OP, the title is misleading. Typescript technically doesn't introduce any new runtime feature. This is basically a polyfill for an upcoming Javascript feature.
franciscop 3y ago
No, I am very familiar with JS and wasn't sure reading the article what bits were the new TC39 proposal and what bits were TS-specific. It seems, from having read it once quickly, that it's just TS adding support early to a feature that will come in JS, similar to how you could add support to async/await in your transpiler before they were commonplace by transforming them into promises back in the day. But that's definitely not a "TS new keyword".

Dylan16807 3y ago

From a brief search, it looks like the semantics around destructuring and what exactly gets disposed were causing confusion? What's the not-C#-like method that would have allowed destructuring in a better way?

hn_throwaway_99 3y ago

> and sabotaged attempts to combine disposal with destructuring. Can you explain by what you mean by this? What would "disposal combined with destructuring" look like?

potsandpans 3y ago

this happens a lot in tc39 proposals unfortunately.

scarab92 3y ago

The overwhelming share of improvements made to Java, Javascript, Typescript etc over the past decade have been inspired by C#, so I can understand why the C# terminology was front of mind. Can you elaborate more of what combining disposal and destructuring would look like?

vips7L 3y ago
I’m not sure Java has taken anything from C#. Most of its recent features have been taken from ML influences.