tsconfig.json "lib": "dom" should include "dom.iterable"(?)

[rauschma]

🔎 Search Terms

lib, dom, dom.iterable

🕗 Version & Regression Information

• An issue as of TypeScript 5.7.2

⏯ Playground Link

No response

💻 Code

// Does TypeScript have the types for DOM iteration?
for (const x of document.querySelectorAll('div')) {}

🙁 Actual behavior

• No error if "lib" is omitted from tsconfig.json.
• Error if "lib" is ["es2024", "DOM"]
• No error if "lib" is ["es2024", "DOM", "DOM.iterable"]

🙂 Expected behavior

Given how broadly supported DOM.iterable is, it should be part of DOM by now(?)

Interestingly, es2024.full looks like this but can’t be used as a value of "lib":

/// <reference lib="es2024" />
/// <reference lib="dom" />
/// <reference lib="webworker.importscripts" />
/// <reference lib="scripthost" />
/// <reference lib="dom.iterable" />
/// <reference lib="dom.asynciterable" />

Additional information about the issue

No response

[RyanCavanaugh]

It's not clear what you would do if you were targeting a browser that doesn't have iterable, though?

[tbroyer]

Fair, I don't think many people do that though. And there are other tools to check compatibility (e.g. ESLint's eslint-plugin-compat); is it really TypeScript's role? (note that I don't have a strong opinion on this)

Fwiw: https://caniuse.com/mdn-api_nodelist_--iterator

[rauschma]

It's not clear what you would do if you were targeting a browser that doesn't have iterable, though?

Interesting consideration! Thoughts:

• Being able to use "es2024.full" seems useful.
• Not sure if that’s feasible but removing features would help in this case:

  "lib": ["DOM", "-DOM.Iterable"]

• The rules for what is and isn’t included in DOM could be mentioned in microsoft/TypeScript-DOM-lib-generator. I thought the following rule applied in this case (but reading it again now, it probably doesn’t): “A feature needs to be supported by two or more major browser engines to be included here”