Microsoft/TypeScript

Suggestion: Support readonly interfaces in `getSuggestedLibFor...`

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#61,323 opened on Mar 1, 2025

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Domain: Error MessagesHelp WantedPossible Improvement

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Description

🔍 Search Terms

readonly target library

✅ Viability Checklist

⭐ Suggestion

Read-only variants of ECMAScript interfaces are currently not eligible for script target suggestions. This is most noticeable with ReadonlyArray, since this type can arise through syntax rather than by referencing the symbol directly.

[1,2,3].toReversed();
//      ~~~~~~~~~~
// Property 'toReversed' does not exist on type 'number[]'. Do you need to change your target library? Try changing the 'lib' compiler option to 'es2023' or later.

([1,2,3] as const).toReversed();
//                 ~~~~~~~~~~
// Property 'toReversed' does not exist on type 'readonly [1, 2, 3]'.

It would be useful if the suggested lib checks could resolve these in the same way.

📃 Motivating Example

As above.

💻 Use Cases

N/A

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