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TypesScript types issue with node with readonly array and .map, .each on AstPath #15034
Description
Environments:
- Prettier Version: 3.0.0
- Running Prettier via: n/a / TypeScript
- Runtime: Node v18.16.0, Typescript 5.1
- Operating System: MacOS
- Prettier plugins (if any): Issue happen when writing a plugin
Typescript produce an error when trying to use .map for a property that is a readonly array.
Steps to reproduce:
Using the following typescript code will produce an error when trying to .map a property that is a readonly array(same for .each)
import { AstPath } from "prettier";
interface TestNode {
regularArray: string[];
readonlyArray: readonly string[];
}
const path: AstPath<TestNode> = undefined as any;
// Works fine
path.map(() => "", "regularArray");
// Ts error
path.map(() => "", "readonlyArray");
// ^ Argument of type '"readonlyArray"' is not assignable to parameter of type '"regularArray"'.ts(2345)Expected behavior:
Should not be any difference between a readonly and regular array.
Actual behavior:
Typescript produce an error when trying to use .map for a property that is a readonly array.
Activity
[-]TypesScript types issue with node with readonly array[/-][+]TypesScript types issue with node with readonly array and `.map`, `.each` on `AstPath`[/+]auvred commentedon Jul 7, 2023
It guess that to fix this issue it is enough to add
readonlyhere:prettier/src/index.d.ts
Line 36 in 6e5dee0
TS Playground
If this is correct, I can submit a PR
timotheeguerin commentedon Jul 7, 2023
yeah, i copied the types after and adding that
readonlyworks, though got into some very bad performance issue in the IDE. Not sure if that was related or due to something else at the same time.Edit: perf issue seems to have been caused by using both
prettier.AstPathand my copy if it at the same time. Typescript didn't seem to like converting between those 2 complex types.