TypeScript 4.3

[sosukesuzuki]

TypeScript 4.3 has been announced. See https://devblogs.microsoft.com/typescript/announcing-typescript-4-3-beta/ .

Status

• typescript: typescript-eslint 4.25.0 supports TS 4.3 features. Also we merged the PR support it(Support TypeScript 4.3 #10945), but not released yet.
• babel-ts: We've shipped TS 4.3 support in Prettier 2.3

New Syntax

get/set for type members

interface Thing {
    get size(): number
    set size(value: number | string | boolean);
}

override modifier in classes

class SpecializedComponent extends SomeComponent {
    override show() {
        // ...
    }
    override hide() {
        // ...
    }
}

static indexed signatures

class Foo {
  static [propName: string]: string | number | undefined;
}

---

Anything else?

[dnalborczyk]

Anything else?

private functions: https://devblogs.microsoft.com/typescript/announcing-typescript-4-3-beta/#ecmascript-private-class-elements

although, it might be already supported?

[worstpractice]

Anything else?

private functions: https://devblogs.microsoft.com/typescript/announcing-typescript-4-3-beta/#ecmascript-private-class-elements

although, it might be already supported?

The private class element syntax (which is actually a JavaScript language feature, and not a TypeScript language feature) seems fully supported by Prettier (atleast as of 2.2.1).

However at the time of this writing, Prettier chokes on the items listed by OP.

[pleerock]

Can we also have a better formatting of using as conditional expressions in object key signatures? For example I don't feel this looks good right now:

export type EntityPrimaryColumnValueMap<
  Entity extends AnyEntity,
  Deepness extends string = "."
> = FlatTypeHint<
  {
    [P in keyof (Entity["columns"] &
      Entity["embeds"]) as EntityPrimaryColumnValueMapAsCondition<
      Entity,
      P
    > extends true
      ? P
      : never]: P extends keyof Entity["columns"]
      ? ColumnCompileType<Entity, P>
      : P extends keyof Entity["embeds"]
      ? EntityPrimaryColumnValueMap<Entity["embeds"][P], `${Deepness}.`>
      : never
  }
>

[alexander-akait]

@pleerock please avoid do it here, your problems is not relevant to this

[thorn0]

@pleerock I opened #10667 for that. Thanks for reporting.

[sosukesuzuki]

Babel 7.14.0 has been released. We can support TS 4.3 via babel-ts now.

[sosukesuzuki]

If TypeScript 4.3 is released, many users would like Prettier to support TS 4.3. Keep this issue pinned until the next release so they don't create extra issues.

[sosukesuzuki]

TypeScript 4.3 has been released https://devblogs.microsoft.com/typescript/announcing-typescript-4-3/

[kirillgroshkov]

What's the plan to release this feature? I guess many folks are blocked with Typescript 4.3 update because of this.. 🙏

[sosukesuzuki]

@kirillgroshkov We haven't decided on the specifics, but I think it needs to be done as soon as possible.

Also you can use the workaround with babel-ts:

{
  "overrides": [
    {
      "files": "*.ts",
      "options": {
        "parser": "babel-ts"
      }
    }
  ]
}

[adrigzr]

Hi, I'm having trouble overriding an abstract property:

abstract class Foo extends Bar {
  abstract override name: string;
}

This gets "prettied" to override abstract which is incorrect:

abstract class Foo extends Bar {
  override abstract name: string;
}

I'm using babel-ts parser.

[sosukesuzuki]

@adrigzr Thank you it is a bug, I've created the PR to fix it #10961

[akphi]

Just curious, do we have some ETA on when this might get released?

[sosukesuzuki]

We've released 2.3.1 that supports TS 4.3.