TypeScript 5.3 Iteration Plan

[DanielRosenwasser]

This document outlines our focused tasks for TypeScript 5.3. 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
2023-08-22	TypeScript 5.2 Release
2023-09-22	Create 5.3 Beta (5.3.0) Build for Testing
2023-09-26	TypeScript 5.3 Beta Release
2023-10-27	Create 5.3 RC (5.3.1) Build for Testing
2023-10-31	TypeScript 5.3 RC Release
2023-11-10	Create 5.3 Final (5.3.2) Build for Testing
2023-11-14	TypeScript 5.3 Final Release 🚀

gantt
    dateFormat  YYYY-MM-DD
    TypeScript 5.2 Stabilization Period : 2023-08-05, 2023-08-24
    TypeScript 5.3 Beta Development : 2023-08-05, 2023-09-22
    TypeScript 5.3 RC Development : 2023-09-23, 2023-10-27
    TypeScript 5.3 Stabilization Period : 2023-10-28, 2023-11-10
todayMarker stroke-width:5px,stroke:#0f0,opacity:0.5

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Compiler and Language

• import Attributes
• Champion throw Expressions
• Isolated Declarations
• Investigate Function Implementations Returning Indexed Access and Conditional Types
• Investigate Interop Across TypeScript and Bundlers for Default Imports
• lib.d.ts Updates

Editor and Language Service

• Interactable Inlay Type Hints
• File-Watching Events over TSServer
• Open-Ended String Completions
• Full Program Loads and ATA in vscode.dev
• Investigate AI-powered Refactorings
• Organize Imports Respecting type Imports
• Experiment with Better Names for Extracted Code
• Specify Node.js Executable for TSServer in VS Code
• Trailing Comma Completions for Snippets
• Investigate Carrying Imports Across Paste
• Address Crawler-Detected Crashes

Performance

• Investigate Parallelized Parsing
• Investigate Caching Resolutions in .tsbuildinfo
• Share Path Resolution Between Projects When Possible
• Optimize JSDoc Parsing
• Deopt Explorer Upkeep

Website and Docs

• Author and Iterate on Module Documentation
• Website Build Speedup

Community Tooling

• Investigate fetch in @types/node
• Use pnpm Workspaces in DefinitelyTyped
• Automated Formatting in DefinitelyTyped

Infrastructure

• Performance Suite Infrastructure Setup
• Expand Performance Suite
• Automated Formatting in Repo

[Andarist]

What's the current status of the "Investigate Type Argument Placeholders" item that was part of the 5.2 milestone?

[DanielRosenwasser]

I don't think we've come up with any better conclusions since the last design meeting discussion about it.

[Andarist]

Does it mean that the topic was dropped for the foreseeable future or is there a chance that it will be discussed again in the near-ish future (like in the next minor or the one after that)? I loved that the related PR (opened in 2018!) got some momentum in 5.2 and I wonder if it just got slowed down or if it stopped entirely for the time being 😅

[omermizr]

@DanielRosenwasser the timeline has wrong versions :)
Also I agree with @Andarist - this is the biggest pain point for me in TS today and would love to see it get some love <3

[DanielRosenwasser]

@DanielRosenwasser the timeline has wrong versions :)

Fixed, thanks!

Does it mean that the topic was dropped for the foreseeable future or is there a chance that it will be discussed again in the near-ish future

It's not out of the question - but big part of the iteration plans is just defining scope so the team can focus and the community gets clarity around that. They're not a promise that we'll get all the work done, nor does it guarantee other work cannot be done.

[Andarist]

That's totally understandable! I just couldn't help but notice that the other exciting item ("Investigate Function Implementations Returning Indexed Access and Conditional Types") from the 5.2 iteration plan was added here but the partial inference thing was not. Hence the question about its status cause I don't think that this investigation was concluded publicly.

[JesusTheHun]

@DanielRosenwasser What those conclusions were ? I've made a crude comment about the current proposal here.

[jiawei397]

I would like to know if there are any plans for Decorators because version 5X does not support ParameterDecorator. Also, when will the support for old version decorators be deprecated, such as the experimentalDecorators configuration?

[jakebailey]

@jiawei397 See https://github.com/tc39/proposal-decorators/blob/master/EXTENSIONS.md#parameter-decorators-and-annotations; TypeScript is just following the spec and won't add it until parameter decorators are Stage 3.