es2020.d.ts is included for a project configured to only use lib:["es5"]

[greyepoxy]

Bug Report

🔎 Search Terms

• lib
• es2020
• esnext
• reference

🕗 Version & Regression Information

This is the behavior in every version I tried, and I reviewed the FAQ for entries about compilerOptions "lib" and "types"

⏯ Playground Link

Couldn't figure out how to add dependencies in the playground so uploaded an example repository:
https://github.com/greyepoxy/typescript-over-lib-inclusion-issue

💻 Code

In a project with the following tsconfig.json excerpt,

{
    "compilerOptions": {
        "lib": ["es5"],
        "types": [],
        "skipLibCheck": true
    }
}

And the following code,

import { shallow } from "enzyme";

const bigInt = BigInt(9007199254740991);

🙁 Actual behavior

Compile succeeds without issue

🙂 Expected behavior

For the compiler to throw an Error because BigInt should not be defined because it is in the es2020 lib which is not included in the compilerOptions

I have done some analysis on why this occurring, please see the root cause section in the example project readme.

Why this Matters

In the company I work for (Tableau), several hundreds of web developers have depended on the tsconfig lib as a tool to try and prevent using new JavaScript features that are not present in IE11 (and other slower to update browsers). With the recent change to @types/node to always include the es2018 and parts of the es2020 lib, there is no way to rely on this compile time check to make sure someone has not started to use a new JavaScript feature unintentionally.

Other Related Issues

There seems to be a other "related" issues, but best as I can tell none that discuss this specific problem.

#41999

#18588

There does appear to a proposal that I believe would address this issue https://gist.github.com/RyanCavanaugh/702ebd1ca2fc060e58e634b4e30c1c1c. Not sure if that means other issues have already been created and closed related to this problem. Apologies if they have.

[greyepoxy]

Just wanted to call out that after digging into the node types history a bit more, seems like the inclusion of lib references has been going on for much longer then I thought. For example
bigint was added Feb 23, 2019
the other references appear to have been added Feb 6, 2019 with the introduction of the first typesVersions
Not sure this really changes anything, more of calling out that unraveling the types is probably not an option at this point.

[RyanCavanaugh]

See also #37053

[greyepoxy]

hmmm, @RyanCavanaugh not sure I understand how this is a duplicate of that item. The problem of test types being available in non-test files seems similar but I do not believe it is the same.

Were you thinking that the solution to that issue would address this issue as well?

[RyanCavanaugh]

The "scope pollution" problem occurs in all of these contexts and has the same speculative fix in each place - some way for the transitive dependencies of types packages to not appear in your program.

[typescript-bot]

This issue has been marked as a 'Duplicate' and has seen no recent activity. It has been automatically closed for house-keeping purposes.