TypeScript 3.6 Iteration Plan

[DanielRosenwasser]

This document outlines our focused tasks for TypeScript 3.6, 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.

Note that this release shifts TypeScript from a 2-month release cycle to a 3-month release cycle.

Dates

• 3.5 ships (May 29th)
• TypeScript 3.6 Beta
  • Snap on July 12th
    • Kick off build for CTI
  • Release on July 16th
• First VS Code Insiders Build: August 1st?
• TypeScript 3.6 RC
  • Snap on August 9th
    • Kick off build for CTI
    • Kick off insiders for VS Code
  • Release on August 13th
• TypeScript 3.6 Final
  • Snap on August 23rd
    • Kick off build for CTI
    • Kick off insiders for VS Code
  • Release on August 27th 🚀

Work Items

Expected Work Items

• Bugs bugs bugs
• Language
  • Strongly typed iterators and generators
  • Stricter types for IteratorResult
  • ECMAScript private instance fields
• Compiler
  • APIs for --incremental builds and project references
  • More accurate array spread
  • UX on Promises
  • Investigate TypeScript plugin APIs
  • --declaration and --allowJs
• Infrastructure
  • Automated testing infrastructure for language service on real world code and DefinitelyTyped
  • Test tiering - faster local tests, longer CI runs
  • Release process overhaul
    • Need to enable automated cherry-picking.
    • Enable experimental feature branching
    • Must document the process here.
    • typescript-bot commenting that PRs don't have associated issues with a milestone
  • Migrate repo to ESLint
• Editor Features
  • Await feedback for more completion priority improvements
  • Automatic Semicolon Deletion for auto-imports/refactors
  • Auto-completion on Promises
  • Call hierarchy
  • TSServer diagnostics command

Deferred Work Items

None from planning meeting

---

Planning Meeting Notes

Motivations

• Bug backlog
• Goals and current 6-month roadmap
• GitHub user feedback (👍s)
• Feedback from customer interviews, social media, past iteration plans
• Visual Studio and Visual Studio Code feedback, as well as new functionality demands
• Actionable PRs (need to make a call)

General (compiler/infrastructure/reliability)

• Bugs bugs bugs
  • We simply haven't caught up with these from 3.4/3.5.
  • Committed ✅
• Strongly typed iterators and generators
  • PR out ✅
• Stricter types for IteratorResult
  • PR out. ✅
• ECMAScript private instance fields
  • PR out. ✅
• APIs for composite projects (--build mode)
  • PR out. ✅
• More accurate array spread.
  • PR out. ✅
• UX on Promises
  • High value for all users, useful to partner teams.
  • Committed ✅
• Investigate TypeScript plugin APIs 🏃
  • Ongoing.
• --declaration and --allowJs
  • Concerns with edge cases.
  • Can use the GitHub crawler to see how stable it is.
  • Do the work and let the crawler find the tail of bugs before we're ready to commit. ✅
• Testing infra
  • Automated testing infrastructure for language service on real world code and DefinitelyTyped
  • Test tiering - faster local tests, longer CI runs
  • Release process overhaul
    • Need to enable automated cherry-picking.
    • Enable experimental feature branching
    • Must document the process here.
    • typescript-bot commenting that PRs don't have associated issues with a milestone.
  • All of these, yes ✅
• Migrate repo to ESLint
  • ✅ Seems doable, @a-tarasyuk seems interested in helping!

Productivity

• Editor Features
  • Await feedback for more completion priority improvements
  • Automatic Semicolon Deletion for auto-imports/refactors
    • One of the most-demanded set of items
    • Committed ✅
  • Auto-completion on Promises
    • Seems useful for partner teams as well as JS users
    • Committed ✅
  • Call hierarchy
    • Ask from VS Code
    • Committed ✅
  • Diagnostics command
    • Seems like it would provide a low-cost high-value way for users to diagnose "TypeScript is slow in my editor."
    • Committed ✅

[fatcerberus]

What’s meant by “snap”? I know it’s a football metaphor, but I’m not sure what it means in terms of release scheduling.

[weswigham]

"snap" short for "snapshot" as in "to capture (a release)" - nothing to do with football in this context, I think.

[fatcerberus]

Oh - I thought it was a football metaphor since the items immediately below are “kick off X”. Thanks, snapshot makes more sense!

[weswigham]

“kick off X” as in "to start X" heh, fair - I think that turn of phrase actually does come from football.

[RyanCavanaugh]

TL;DR during the next over we're scrumming the uprights and chipping the wicket.

[DanielRosenwasser]

I thought it was about branches snapping like on a tree even though that actually makes no sense since the branches are growing, not breaking.

[falsandtru]

You should put up #32273 on the working list and address it.

[falsandtru]

You should release #32283 with the next release to make complete user experience of enhanced generators.

[ericanderson]

@DanielRosenwasser Is 3.6.3 ready to go out? Could we get an rc if not?

[DanielRosenwasser]

Would you be able to validate typescript@3.6.3-insiders.20190909 for us?

[ericanderson]

First pass of testing suggests this will solve our problem. I need to run the full suite of builds/tests over night (2x) to be sure but if it pans out, I'll push this insider build to our devs tomorrow.

[kjleitz]

@DanielRosenwasser The typescript@3.6.3-insiders.20190909 release fixes our issues (vuejs/vue#10455) as well (see also #33164). Solved all of the 100+ build errors!

[DanielRosenwasser]

Thanks everyone! As a final update before I close this out:

• 3.6.3 is available.
• We may provide a 3.6.4 with changes related to tree transforms and generators.
• the 3.7 iteration plan is now available: TypeScript 3.7 Iteration Plan #33352