TypeScript 4.7 Iteration Plan

[DanielRosenwasser]

This document outlines our focused tasks for TypeScript 4.7. It minimally indicates intent to investigate tasks or contribute to an implementation. Nothing is set in stone, but we will strive to complete these tasks in a reasonable timeframe.

Date	Event
TBD	TypeScript 4.6 Release
April 1st	Create 4.7 Beta (4.7.0) Build for Testing
April 5th	TypeScript 4.7 Beta Release
May 6th	Create 4.7 RC (4.7.1) Build for Testing
May 10th	TypeScript 4.7 RC Release
May 20th	Create 4.7 Final (4.7.2) Build for Testing
May 24th	TypeScript 4.7 Final Release 🚀

Language and Compiler Features

• Node ESM UX Issues, and Move Node ESM Mode from Nightly
• Instantiation Expressions
• Import Strategies for import type and /// <reference />
• Investigate Contextually Typed And Compatible Operator
• lib.d.ts Updates

Editor Productivity

• Object Member Snippet Completions
• Investigate Go to JavaScript Implementation
• Prototype Virtual File System Support in TSServer
• Prototype Automatic Type Acquisition in Web Contexts
• Easy Run/Debug for Loose TypeScript Files
• Investigate TS Server Plugins on the Web

Performance

• Investigate Outstanding Performance Issues
• Find All References Refactoring and Optimizations
• Supporting Additional Trace Points
• Profiling/Tracing Mode Improvements
• Investigate Tooling for JIT Deoptimizations

Infrastructure

• Migrate to Modules
• Determine Shipping Strategy for Modules
• Fuzzer Improvements and Addressing Crashes
• Improving User Suite Reports
• Expand Perf Suite

Website

• Investigate Playground as a VS Code Extension

[vietanhtran16]

Hello, I am not sure if this is the right place for this but we got the below issue with version 4.7.0-dev.20220320 (this is automatically selected by VSCode) like the below image. We did some testing and noticed that this issue does not show up for version below 4.7.0, in our case 4.6.2 and 4.1.5 work fine. If this is not the right place for this, please let me know. Thanks

Context:

• We provide type safe fetch (its type is quite nested) which allows us to safely type the response based on the url of the request we are trying to make for a good dev experience
• We are getting the below error when we use our fetch in a Promise.all. My assumption is that Promise.all
  is trying to infer the type from our fetch type which is quite nested and caused this error on 4.7.0-dev.20220320

const [responseOne, responseTwo] = await Promise.all([ // it complains about the below error here
    fetch("https://something/v1", { req, timeout: 5000 }),
    fetch(
      "https://something/v2",
      { req, timeout: 5000 }
    )
  ])

[aladdin-add]

@vietanhtran16 yes, the issue is not for bug report, please file a new issue. :)

[vietanhtran16]

@vietanhtran16 yes, the issue is not for bug report, please file a new issue. :)

Cool I will file a new one

[DanielRosenwasser]

@typescript-bot create release-4.7

[typescript-bot]

Heya @DanielRosenwasser, I've started to create the release-4.7 branch for you. Here's the link to my best guess at the log.

[DanielRosenwasser]

Looks like it's probably failing because of the Node ESM stuff which we were hoping to unflag for the beta at the least. There's also some basic bug fixes I'd like us to pull in before beta, so maybe we'll go out on April 6th instead.

[DanielRosenwasser]

@typescript-bot create release-4.7

[typescript-bot]

Heya @DanielRosenwasser, I've started to create the release-4.7 branch for you. Here's the link to my best guess at the log.

[DanielRosenwasser]

The feature roadmap now better-reflects what we've been able to get done for 4.7.

[Jack-Works]

I still want to suggest typescript to drop Node 12 in new Node ESM. Lets start from Node 14. Node 14 has TLA support.

Node 12 will end LTS this month.

[lvelden]

Hi! I've seen the 4.7-beta announcement, but it's not listed under releases and there's also no v4.7-beta tag. Are you planning on adding this?

[DanielRosenwasser]

Sorry, tag for 4.7 beta should be out https://github.com/microsoft/TypeScript/releases/tag/v4.7-beta

[diervo]

@DanielRosenwasser is there a specific tag or semantics for filing issues against this beta that will help streamline the process?

[DanielRosenwasser]

Just open up issues and fill out the template, maybe signal specifically whether you've found a regression or a bug in a new feature.

[DanielRosenwasser]

We've moved resolution-mode from import type and export type into nightly-only, so I cannot summon the bot. The bump to RC is at #49007.

[DanielRosenwasser]

4.8 Iteration Plan is available at #49074

[RyanCavanaugh]

@typescript-bot bump release-4.7

[typescript-bot]

Heya @RyanCavanaugh, I've started to update the version number on release-4.7 to 4.7.2 for you. Here's the link to my best guess at the log.

[Jamesernator]

Just wanted to point out one mistake in the TypeScript 4.7 RC release notes that should probably be fixed for the full release and that's that the line:

Certain global-like values like require() and process cannot be used directly.

Is actually incorrect for process, unlike require which a per-cjs-module injected thing, the process object is actually just a property of global so is usable in ESM as a global without problems.

An alternative object for the sentence could the module per-cjs-module object i.e.:

Certain global-like values like require() and module cannot be used directly.

[DanielRosenwasser]

Thank you for that correction!

[DanielRosenwasser]

TypeScript 4.7 is now out!

[HolgerJeromin]

Happy to test, but linked Typescript SDK has a 404 and nuget.org has a 4.7.2-rc (hu?).
But npm is available :-)

ref #48456

[DensedyGot]

I installed the typescript 4.7.2 but I encountered an error

Module build failed (from ./node_modules/ts-loader/index.js):
Error: Debug Failure. False expression: Non-string value passed to ts.resolveTypeReferenceDirective, likely by a wrapping package working with an outdated resolveTypeReferenceDirectives signature. This is probably not a problem in TS itself.

I'm using Node@16.15.0 and npm@8.11.0

Here are some of the packages I used
@fluentui/react@8.70.0
@types/react@17.0.45
react@17.0.2
react-dom@7.0.2
@types/node@16.11.36
@typescript-eslint/eslint-plugin@4.29.0
@typescript-eslint/parser@4.29.0
eslint@7.32.0
eslint-config-standard@16.0.2
eslint-plugin-import@2.26.0
eslint-plugin-node@11.1.0
eslint-plugin-promise@5.1.0
typescript@4.7.2

[DanielRosenwasser]

@typescript-bot bump release-4.7

[typescript-bot]

Heya @DanielRosenwasser, I've started to update the version number on release-4.7 to 4.7.3 for you. Here's the link to my best guess at the log.

[DanielRosenwasser]

@typescript-bot bump release-4.7

[typescript-bot]

Heya @DanielRosenwasser, I've started to update the version number on release-4.7 to 4.7.4 for you. Here's the link to my best guess at the log.