Add ESLint rule for Node.js type stripping compatibility

[Copilot]

Motivation for the change, related issues

Node.js type stripping (--experimental-strip-types) fails on TypeScript syntax with runtime semantics. This caused runtime errors like:

SyntaxError [ERR_UNSUPPORTED_TYPESCRIPT_SYNTAX]: TypeScript parameter property is not supported

Implementation details

Added the existing @typescript-eslint/parameter-properties ESLint rule to prevent TypeScript parameter properties that are unsupported by Node.js type stripping.

• Parameter properties — constructor(private foo: string) → explicit property + assignment

Fixed existing violations:

• blueprints-v1-handler.ts, blueprints-v2-handler.ts, website-page.ts, code-editor.tsx — converted parameter properties to explicit declarations

Testing Instructions (or ideally a Blueprint)

npm run lint

Verify the rule catches new violations:

// Should error
class Foo {
  constructor(private bar: string) {}
}

Original prompt

Start a new PR to add an eslint rule – only allow TypeScript syntax that's supported by Node.js type stripping (to prevent future errors such as this):

Version number df6471b7770cee7792040577 copied to clipboard
Use Ctrl+C to stop the server
node:internal/modules/run_main:123
triggerUncaughtException(
^

file:///Users/mho/Work/projects/xdebug/wordpress-playground/packages/playground/blueprints/src/lib/v1/compile.ts:47
export class InvalidBlueprintError extends Error {
constructor(message: string, public readonly validationErrors?: unknown) {
^^^^^^^^^^^^^^^^^^^^^^^^^^
super(message);

SyntaxError [ERR_UNSUPPORTED_TYPESCRIPT_SYNTAX]: TypeScript parameter property is n
40 references
Copilot said: Let me search for more specific ESLint
Let me search for more specific ESLint configuration files in the repository:Based on my research into the WordPress Playground repository, I can see that:

The repo already has a custom ESLint plugin at packages/meta/src/eslint-plugin-playground-dev/ with one existing rule (avoid-wordpress-builds-dependency)
The root .eslintrc.json already has some Node.js type stripping support with @typescript-eslint/consistent-type-imports rule enabled
The error you referenced is about TypeScript parameter properties (like public readonly validationErrors), which are not supported by Node.js type stripping. A new ESLint rule should be added to prevent this syntax.

I'll create a PR that adds an ESLint rule to disallow TypeScript syntax that's unsupported by Node.js type stripping, specifically:

Parameter properties (constructor(public foo: string))
Enums (which also aren't supported by type stripping)
Namespaces

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[mho22]

There is an existing Typescript Eslint rule named : @typescript-eslint/parameter-properties that could help here I think.

[adamziel]

@copilot apply previous suggestion

[Copilot]

There is an existing Typescript Eslint rule named : @typescript-eslint/parameter-properties that could help here I think.

Applied in 5de6f73. Now using @typescript-eslint/parameter-properties for parameter properties, and the custom rule only handles enums and namespaces with value statements.

[mho22]

@adamziel actually the TS-eslint rule fixes the issue I had, I am not sure the two other issues this pull request tackles about enum and namespace are necessary.

[adamziel]

@copilot We don't need a custom packages/meta/src/eslint-plugin-playground-dev/no-unsupported-typescript-syntax.js rule and also undo the change to packages/docs/site/src/typedoc-model.ts – disable the rule for the offending declaration.

[Copilot]

@copilot We don't need a custom packages/meta/src/eslint-plugin-playground-dev/no-unsupported-typescript-syntax.js rule and also undo the change to packages/docs/site/src/typedoc-model.ts – disabl...

Done in f8f4f8a. Removed the custom no-unsupported-typescript-syntax rule and restored typedoc-model.ts to use the original enum. The PR now only adds the @typescript-eslint/parameter-properties rule.