[@types/styled-components] tsserver running at 100% CPU

If you know how to fix the issue, make a pull request instead.

• I tried using the @types/xxxx package and had problems.
• I tried using the latest stable version of tsc. https://www.npmjs.com/package/typescript
• I have a question that is inappropriate for StackOverflow. (Please ask any appropriate questions there).
• Mention the authors (see Definitions by: in index.d.ts) so they can respond.
  • Authors: @Igorbek @Igmat @lavoaster @Jessidhia

Versions

• @types/styled-components@4.1.14
• typescript@3.3.3

Summary

Upon upgrading to the latest version of @types/styled-components and using VS Code, I noticed that editing typescript files was suddenly causing my CPU usage to jump to 100%. My editor's typescript auto-complete features and lint warnings suddenly took multiple seconds to resolve after typing each character.

On further investigation, I could see that tsserver.js was responsible for all of that CPU usage. Downgrading one version at a time, I was able to isolate the performance slowdown to something that changed between @types/styled-components@4.0.3 and @types/styled-components@4.1.0.

It looks like the two commits added in that version are:

https://github.com/DefinitelyTyped/DefinitelyTyped/commit/5c49d4ddc6f5bd06c5cf04d911398f3db05ead54#diff-9726c25d6953300e0670141c0abac3db

https://github.com/DefinitelyTyped/DefinitelyTyped/commit/59ab5b3aef80fa55010f7d8385f785514d2e0b1a#diff-9726c25d6953300e0670141c0abac3db

To reproduce

1. In a new typescript project:

yarn add typescript@3.3.3 styled-components@4.2.0 @types/styled-components@4.1.0

2. Import styled-components and begin editing the file.

This issue seems similar, but not exactly the same: https://github.com/DefinitelyTyped/DefinitelyTyped/issues/34391

Reproduce the slowdown with the listed TypeScript, styled-components, and @types/styled-components versions, then compare the two linked commits that changed the styled-components definitions. Confirm the fix removes the tsserver 100% CPU behavior and restores responsive autocomplete and lint warnings while editing.