TypeScript 4.2 Iteration Plan

[DanielRosenwasser]

This document outlines our focused tasks for TypeScript 4.2, as well as some of the discussion that explains how/why we prioritized certain work items. Nothing is set in stone, but we will strive to complete them in a reasonable timeframe.

Date	Event
November 19th	TypeScript 4.1 Release
January 8th	Create 4.2 Beta (4.2.0) Build for Testing
January 12th	TypeScript 4.2 Beta Release
February 5th	Create 4.2 RC (4.2.1) Build for Testing
February 9th	TypeScript 4.2 RC Release
February 19th	Create 4.2 Final (4.2.2) Build for Testing
February 23rd	TypeScript 4.2 Final Release 🚀

Language Features

• Generalized index signatures
• Leading/middle rest elements in tuple types
• --noImplicitOverride
• --noPropertyAccessFromIndexSignature
• static Index Signatures
• Investigate typeof class
• Review the project setup experience
• Investigate faster compile-time iteration

Editor Productivity

• Declare missing helper function
• Enable running TSServer in a worker thread
• Anticipated bug fixes and UX improvements for partial semantic mode
• Investigate high-confidence "did you mean?" in JS

Performance

• Profiling/Tracing Mode Improvements

Infrastructure

• Perf Regression Tracking
  • Committing Scripts to Repo
  • Integrate into Release Activities
• Perf Suite Reliability

[jogibear9988]

Is there a way to suggest issues/tasks for a TS release?

[DanielRosenwasser]

Vote on existing issues, or file a new one if one doesn't already exist. We do pay attention to a few of the nudges in these threads, but really discourage people from turning the entire thread into a discussion point for a single feature.

[x87]

https://www.typescriptlang.org/ shows the next version as 4.1, and the link points here:

[RyanCavanaugh]

cc @orta re that

[ExE-Boss]

This file needs fixing: https://github.com/microsoft/TypeScript-Website/blob/v2/packages/typescriptlang-org/src/lib/release-plan.json (the latest commit only updated the dates and the URL: microsoft/TypeScript-Website@cc80197)

[RyanCavanaugh]

Thanks for the quick pointer @ExE-Boss, I've fixed it

[orta]

Thanks folks!

[orta]

Linking the lib DOM changes issue: microsoft/TypeScript-DOM-lib-generator#960

[DanielRosenwasser]

Heads up, lots of people are just coming back from vacation, so we'll be releasing the beta next week instead.

[DanielRosenwasser]

@typescript-bot create release-4.2

[typescript-bot]

Heya @DanielRosenwasser, I've started to create the release-4.2 branch for you. Here's the link to my best guess at the log.

[DanielRosenwasser]

Looks like the "origin types" PR (#42149) has broken the baselines, which is making tests fail.

[DanielRosenwasser]

@typescript-bot create release-4.2

[typescript-bot]

Heya @DanielRosenwasser, I've started to create the release-4.2 branch for you. Here's the link to my best guess at the log.

[DanielRosenwasser]

@typescript-bot sync release-4.2

[typescript-bot]

Heya @DanielRosenwasser, I've started to sync release-4.2 with master for you. Here's the link to my best guess at the log.

[remcohaszing]

TypeScript 4.2 also supports XML namespaces in JSX (#11833). This is missing from the list of new language features as well as from the blogpost on https://devblogs.microsoft.com/typescript/announcing-typescript-4-2-beta.

[brad4d]

There doesn't currently appear to be a v4.2-beta tag.
Shouldn't there be one, since the 4.2 announcement went out?

The Google TSJS team needs a tag to import.

Thanks

[DanielRosenwasser]

@brad4d sorry about that, it should be published now

https://github.com/microsoft/TypeScript/releases/tag/v4.2-beta

[DanielRosenwasser]

We had to move the dates to accommodate a few fixes that came in today. We'll likely be releasing the RC on the 11th.

[DanielRosenwasser]

@typescript-bot sync release-4.2

[typescript-bot]

Heya @DanielRosenwasser, I've started to sync release-4.2 with master for you. Here's the link to my best guess at the log.

[DanielRosenwasser]

@typescript-bot bump release-4.2

[typescript-bot]

Heya @DanielRosenwasser, I've started to update the version number on release-4.2 to 4.2.1-rc for you. Here's the link to my best guess at the log.

[jogibear9988]

shouldn't this one be closed #40124 as 4.2 is nearly ready?

[Jack-Works]

I have a suggestion, when a new iteration plan opened, post a link at the old iteration plan so people can follow

[longlho]

Can #42134 be revised/reverted please?

[DanielRosenwasser]

@typescript-bot bump release-4.2

[typescript-bot]

Heya @DanielRosenwasser, I've started to update the version number on release-4.2 to 4.2.2 for you. Here's the link to my best guess at the log.

[DanielRosenwasser]

@typescript-bot bump release-4.2

[typescript-bot]

Heya @DanielRosenwasser, I've started to update the version number on release-4.2 to 4.2.3 for you. Here's the link to my best guess at the log.

[Jack-Works]

Reverse link to 4.3 iteration plan #42762 (mentioned from 4.3 iteration plan won't send mail to people who subscribed to 4.2 iteration plan)

[DanielRosenwasser]

@typescript-bot bump release-4.2

[typescript-bot]

Heya @DanielRosenwasser, I've started to update the version number on release-4.2 to 4.2.4 for you. Here's the link to my best guess at the log.

[aslatter]

FYI - it looks like NPM has a version 4.2.4, but GitHub doesn't have a tag v4.2.4 or a release for 4.2.4.

[brad4d]

Can we expect to have a v4.2.4 defined by 2021-04-12, or is more time needed before that can happen?
Within Google we're anxious to get the fix for JSDoc annotations getting copied to overloads.
It's causing spurious deprecation warnings for our users.
We need an official v4.2.4 tag so we can upgrade.
Thanks.

[orta]

@brad4d shipped - https://github.com/microsoft/TypeScript/releases/tag/v4.2.4

[longlho]

Can I get #42945 in as well?